CompareInfo.LastIndexOf Metodo

Definizione

Spazio dei nomi:: System.Globalization

Assembly:: mscorlib.dll, System.Globalization.dll

Assembly:: mscorlib.dll

Assembly:: System.Globalization.dll

Assembly:: netstandard.dll

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Restituisce l'indice in base zero dell'ultima occorrenza di un valore all'interno di una stringa o all'interno di una parte di esso.

Overload

Nome	Descrizione
LastIndexOf(String, Char, Int32, Int32, CompareOptions)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che contiene il numero specificato di elementi e termina in corrispondenza dell'indice specificato utilizzando il valore specificato CompareOptions .
LastIndexOf(String, String, Int32, Int32)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine contenente il numero specificato di elementi e termina in corrispondenza dell'indice specificato.
LastIndexOf(String, String, Int32, Int32, CompareOptions)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine contenente il numero specificato di elementi e termina in corrispondenza dell'indice specificato utilizzando il valore specificato CompareOptions .
LastIndexOf(String, String, Int32, CompareOptions)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato utilizzando il valore specificato CompareOptions .
LastIndexOf(String, Char, Int32, Int32)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine contenente il numero specificato di elementi e termina in corrispondenza dell'indice specificato.
LastIndexOf(String, Char, Int32, CompareOptions)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato utilizzando il valore specificato CompareOptions .
LastIndexOf(String, Char, CompareOptions)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine usando il valore specificato CompareOptions .
LastIndexOf(String, String, CompareOptions)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine usando il valore specificato CompareOptions .
LastIndexOf(String, Char, Int32)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato.
LastIndexOf(String, String)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine.
LastIndexOf(String, Char)	Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine.
LastIndexOf(String, String, Int32)	Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato.

LastIndexOf(String, Char, Int32, Int32, CompareOptions)

Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che contiene il numero specificato di elementi e termina in corrispondenza dell'indice specificato utilizzando il valore specificato CompareOptions .

public:
 virtual int LastIndexOf(System::String ^ source, char value, int startIndex, int count, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, char value, int startIndex, int count, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * char * int * int * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * char * int * int * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As Char, startIndex As Integer, count As Integer, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

count: Int32

Numero di elementi nella sezione da cercare.

options: CompareOptions

Valore che definisce come source e value deve essere confrontato. optionsè il valore Ordinaldi enumerazione o una combinazione bit per bit di uno o più dei valori seguenti: IgnoreCase, IgnoreSymbols IgnoreNonSpace, IgnoreWidth, e IgnoreKanaType.

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di value, se trovato, all'interno della sezione di source che contiene il numero di elementi specificati da count e che termina in startIndex, utilizzando le opzioni di confronto specificate; in caso contrario, -1. Restituisce startIndex se value è un carattere ignorabile.

Eccezioni

ArgumentNullException

source è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

oppure

count è minore di zero.

oppure

startIndex e count non specificano una sezione valida in source.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una parte di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 8;
      // iL is the length of the substring.
      int iL = 18;
      // myT1 and myT2 are the strings used for padding.
      String myT1 = new String( '-', iS );
      String myT2;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

Original      : Is AE or ae the same as Æ or æ?
No options    : -------- ae the same as Æ -----
           AE :                         b
           ae :          b
            Æ :                         b
            æ :          b
Ordinal       : -------- ae the same as Æ -----
           AE :
           ae :          b
            Æ :                         b
            æ :
IgnoreCase    : -------- ae the same as Æ -----
           AE :          f              l
           ae :          f              l
            Æ :          f              l
            æ :          f              l

Original      : Is U" or u" the same as Ü or ü?
No options    : -------- u" the same as Ü -----
           U" :                         b
           u" :          b
            Ü :                         b
            ü :          b
Ordinal       : -------- u" the same as Ü -----
           U" :
           u" :          b
            Ü :                         b
            ü :
IgnoreCase    : -------- u" the same as Ü -----
           U" :          f              l
           u" :          f              l
            Ü :          f              l
            ü :          f              l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 8
      ' iL is the length of the substring.
      Dim iL As Integer = 18
      ' myT1 and myT2 are the strings used for padding.
      Dim myT1 As New [String]("-"c, [iS])
      Dim myT2 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------- ae the same as Æ -----
'           AE :                         b
'           ae :          b
'            Æ :                         b
'            æ :          b
'Ordinal       : -------- ae the same as Æ -----
'           AE :
'           ae :          b
'            Æ :                         b
'            æ :
'IgnoreCase    : -------- ae the same as Æ -----
'           AE :          f              l
'           ae :          f              l
'            Æ :          f              l
'            æ :          f              l
'
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------- u" the same as Ü -----
'           U" :                         b
'           u" :          b
'            Ü :                         b
'            ü :          b
'Ordinal       : -------- u" the same as Ü -----
'           U" :
'           u" :          b
'            Ü :                         b
'            ü :
'IgnoreCase    : -------- u" the same as Ü -----
'           U" :          f              l
'           u" :          f              l
'            Ü :          f              l
'            ü :          f              l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina con startIndex - count + 1.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Se options non include il Ordinal valore, questo overload esegue una ricerca sensibile alle impostazioni cultura. Se il carattere è un valore Unicode che rappresenta un carattere precomposto, ad esempio la legatura "Æ" (U+00C6), può essere considerata equivalente a qualsiasi occorrenza dei relativi componenti nella sequenza corretta, ad esempio "AE" (U+0041, U+0045), a seconda delle impostazioni cultura. Se options include il Ordinal valore , questo overload esegue una ricerca ordinale (senza distinzione tra impostazioni cultura). Un carattere viene considerato equivalente a un altro carattere solo se i valori Unicode sono uguali. Gli overload di String.LastIndexOf tale ricerca di un carattere eseguono una ricerca ordinale, mentre quelli che cercano una stringa eseguono una ricerca sensibile alle impostazioni cultura.

Annotazioni

Quando possibile, è necessario chiamare metodi di confronto di stringhe con un parametro di tipo CompareOptions per specificare il tipo di confronto previsto. Come regola generale, usare le opzioni linguistiche (con la cultura corrente) per confrontare le stringhe visualizzate nell'interfaccia utente e specificare CompareOptions.Ordinal o CompareOptions.OrdinalIgnoreCase per confronti di sicurezza.

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char, Int32, Int32, CompareOptions) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca. Nell'esempio seguente il LastIndexOf(String, Char, Int32, Int32, CompareOptions) metodo viene usato per trovare un trattino morbido (U+00AD) che precede l'ultimo "m" in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, una ricerca sensibile alle impostazioni cultura restituisce la posizione di indice di "m", ovvero il valore di startIndex. Una ricerca ordinale, tuttavia, trova correttamente il trattino morbido in una stringa e segnala che è assente dalla seconda stringa.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      int position = 0;

      // Find the index of the soft hyphen using culture-sensitive comparison.
      position = ci.LastIndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position,
                           position + 1, CompareOptions.IgnoreCase));

      position = ci.LastIndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position,
                           position + 1, CompareOptions.IgnoreCase));

      // Find the index of the soft hyphen using ordinal comparison.
      position = ci.LastIndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position, CompareOptions.Ordinal);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position,
                           position + 1, CompareOptions.Ordinal));

      position = ci.LastIndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position, CompareOptions.Ordinal);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position,
                           position + 1, CompareOptions.Ordinal));
   }
}
// The example displays the following output:
//       'm' at position 4
//       4
//       'm' at position 3
//       3
//       'm' at position 4
//       3
//       'm' at position 3
//       -1

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As Char = ChrW(&h00AD)
      Dim position As Integer
      
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen using culture-sensitive comparison.
      position = ci.LastIndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position, _
                           position + 1, CompareOptions.IgnoreCase))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position, _
                           position + 1, CompareOptions.IgnoreCase))
      End If  
       
      ' Find the index of the soft hyphen using ordinal comparison.
      position = ci.LastIndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position, _
                           position + 1, CompareOptions.Ordinal))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position, _
                           position + 1, CompareOptions.Ordinal))
      End If   
   End Sub
End Module
' The example displays the following output:
'       'm' at position 4
'       4
'       'm' at position 3
'       3
'       'm' at position 4
'       3
'       'm' at position 3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, String, Int32, Int32)

Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine contenente il numero specificato di elementi e termina in corrispondenza dell'indice specificato.

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value, int startIndex, int count);

public virtual int LastIndexOf(string source, string value, int startIndex, int count);

abstract member LastIndexOf : string * string * int * int -> int
override this.LastIndexOf : string * string * int * int -> int

Public Overridable Function LastIndexOf (source As String, value As String, startIndex As Integer, count As Integer) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

count: Int32

Numero di elementi nella sezione da cercare.

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di value, se trovato, all'interno della sezione di source che contiene il numero di elementi specificati da count e che termina in startIndex; in caso contrario, -1. Restituisce startIndex se value è un carattere ignorabile.

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

oppure

count è minore di zero.

oppure

startIndex e count non specificano una sezione valida in source.

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una parte di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 8;
      // iL is the length of the substring.
      int iL = 18;
      // myT1 and myT2 are the strings used for padding.
      String myT1 = new String( '-', iS );
      String myT2;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

Original      : Is AE or ae the same as Æ or æ?
No options    : -------- ae the same as Æ -----
           AE :                         b
           ae :          b
            Æ :                         b
            æ :          b
Ordinal       : -------- ae the same as Æ -----
           AE :
           ae :          b
            Æ :                         b
            æ :
IgnoreCase    : -------- ae the same as Æ -----
           AE :          f              l
           ae :          f              l
            Æ :          f              l
            æ :          f              l

Original      : Is U" or u" the same as Ü or ü?
No options    : -------- u" the same as Ü -----
           U" :                         b
           u" :          b
            Ü :                         b
            ü :          b
Ordinal       : -------- u" the same as Ü -----
           U" :
           u" :          b
            Ü :                         b
            ü :
IgnoreCase    : -------- u" the same as Ü -----
           U" :          f              l
           u" :          f              l
            Ü :          f              l
            ü :          f              l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 8
      ' iL is the length of the substring.
      Dim iL As Integer = 18
      ' myT1 and myT2 are the strings used for padding.
      Dim myT1 As New [String]("-"c, [iS])
      Dim myT2 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------- ae the same as Æ -----
'           AE :                         b
'           ae :          b
'            Æ :                         b
'            æ :          b
'Ordinal       : -------- ae the same as Æ -----
'           AE :
'           ae :          b
'            Æ :                         b
'            æ :
'IgnoreCase    : -------- ae the same as Æ -----
'           AE :          f              l
'           ae :          f              l
'            Æ :          f              l
'            æ :          f              l
'
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------- u" the same as Ü -----
'           U" :                         b
'           u" :          b
'            Ü :                         b
'            ü :          b
'Ordinal       : -------- u" the same as Ü -----
'           U" :
'           u" :          b
'            Ü :                         b
'            ü :
'IgnoreCase    : -------- u" the same as Ü -----
'           U" :          f              l
'           u" :          f              l
'            Ü :          f              l
'            ü :          f              l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina con startIndex - count + 1.

Questo overload esegue una ricerca sensibile alle impostazioni cultura. Un valore Unicode che rappresenta un carattere precomposto, ad esempio la legatura "Æ" (U+00C6), può essere considerata equivalente a qualsiasi occorrenza dei componenti del carattere nella sequenza corretta, ad esempio "AE" (U+0041, U+0045), a seconda delle impostazioni cultura. Per eseguire una ricerca ordinale (senza distinzione tra impostazioni cultura), in cui vengono confrontati i valori Unicode, è necessario chiamare uno degli overload con un parametro di tipo CompareOptions e usare il Ordinal valore .

Annotazioni

Quando possibile, è necessario chiamare metodi di confronto di stringhe con un parametro di tipo CompareOptions per specificare il tipo di confronto previsto. Come regola generale, usare le opzioni linguistiche (usando le impostazioni cultura correnti) per confrontare le stringhe visualizzate nell'interfaccia utente e specificare CompareOptions.Ordinal o CompareOptions.OrdinalIgnoreCase per i confronti di sicurezza .

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value contiene un carattere ignorabile, il risultato equivale alla ricerca con tale carattere rimosso. Se value è costituito solo da uno o più caratteri ignorabili, il LastIndexOf(String, String, Int32, Int32) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca.

Nell'esempio seguente il LastIndexOf(String, String, Int32, Int32) metodo viene usato per trovare la posizione di un trattino morbido (U+00AD) seguito da un "m" nei tre caratteri che precedono il "m" finale di due stringhe. Solo una delle stringhe contiene la sottostringa necessaria. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce l'indice di "m" nella stringa quando esegue un confronto sensibile alle impostazioni cultura. Si noti che nel caso della prima stringa, che include il trattino morbido seguito da un "m", il metodo non restituisce l'indice del trattino morbido, ma restituisce invece l'indice di "m".

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string searchString = "\u00ADm";
      string s1 = "ani\u00ADmal" ;
      string s2 = "animal";
      int position;

      position = ci.LastIndexOf(s1, 'm');
      if (position >= 0) {
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, 3, CompareOptions.None));
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, 3, CompareOptions.Ordinal));
      }

      position = ci.LastIndexOf(s2, 'm');
      if (position >= 0) {
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, 3, CompareOptions.None));
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, 3, CompareOptions.Ordinal));
      }
   }
}
// The example displays the following output:
//       4
//       3
//       3
//       -1

Imports System.Globalization

Public Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo

      Dim searchString As String = ChrW(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal" 
      Dim s2 As String = "animal"
      Dim position As Integer

      position = ci.LastIndexOf(s1, "m"c)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, 3, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, 3, CompareOptions.Ordinal))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, 3, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, 3, CompareOptions.Ordinal))
      End If
   End Sub
End Module
' The example displays the following output:
'       4
'       3
'       3
'       -1

Vedi anche

IndexOf(String, Char)

Si applica a

LastIndexOf(String, String, Int32, Int32, CompareOptions)

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value, int startIndex, int count, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, string value, int startIndex, int count, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * string * int * int * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * string * int * int * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As String, startIndex As Integer, count As Integer, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

count: Int32

Numero di elementi nella sezione da cercare.

options: CompareOptions

Valori restituiti

Int32

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

oppure

count è minore di zero.

oppure

startIndex e count non specificano una sezione valida in source.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una parte di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 8;
      // iL is the length of the substring.
      int iL = 18;
      // myT1 and myT2 are the strings used for padding.
      String myT1 = new String( '-', iS );
      String myT2;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

Original      : Is AE or ae the same as Æ or æ?
No options    : -------- ae the same as Æ -----
           AE :                         b
           ae :          b
            Æ :                         b
            æ :          b
Ordinal       : -------- ae the same as Æ -----
           AE :
           ae :          b
            Æ :                         b
            æ :
IgnoreCase    : -------- ae the same as Æ -----
           AE :          f              l
           ae :          f              l
            Æ :          f              l
            æ :          f              l

Original      : Is U" or u" the same as Ü or ü?
No options    : -------- u" the same as Ü -----
           U" :                         b
           u" :          b
            Ü :                         b
            ü :          b
Ordinal       : -------- u" the same as Ü -----
           U" :
           u" :          b
            Ü :                         b
            ü :
IgnoreCase    : -------- u" the same as Ü -----
           U" :          f              l
           u" :          f              l
            Ü :          f              l
            ü :          f              l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 8
      ' iL is the length of the substring.
      Dim iL As Integer = 18
      ' myT1 and myT2 are the strings used for padding.
      Dim myT1 As New [String]("-"c, [iS])
      Dim myT2 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------- ae the same as Æ -----
'           AE :                         b
'           ae :          b
'            Æ :                         b
'            æ :          b
'Ordinal       : -------- ae the same as Æ -----
'           AE :
'           ae :          b
'            Æ :                         b
'            æ :
'IgnoreCase    : -------- ae the same as Æ -----
'           AE :          f              l
'           ae :          f              l
'            Æ :          f              l
'            æ :          f              l
'
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------- u" the same as Ü -----
'           U" :                         b
'           u" :          b
'            Ü :                         b
'            ü :          b
'Ordinal       : -------- u" the same as Ü -----
'           U" :
'           u" :          b
'            Ü :                         b
'            ü :
'IgnoreCase    : -------- u" the same as Ü -----
'           U" :          f              l
'           u" :          f              l
'            Ü :          f              l
'            ü :          f              l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina con startIndex - count + 1.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Se options non include il Ordinal valore, questo overload esegue una ricerca sensibile alle impostazioni cultura. Un valore Unicode che rappresenta un carattere precomposto, ad esempio la legatura "Æ" (U+00C6), può essere considerata equivalente a qualsiasi occorrenza dei componenti del carattere nella sequenza corretta, ad esempio "AE" (U+0041, U+0045), a seconda delle impostazioni cultura. Se options include il Ordinal valore, questo overload esegue una ricerca ordinale (senza distinzione tra impostazioni cultura), in cui vengono confrontati i valori Unicode.

Annotazioni

Note per i chiamanti

Nell'esempio seguente, il LastIndexOf(String, String, Int32, Int32, CompareOptions) metodo viene usato per trovare la posizione di un trattino morbido (U+00AD) seguito da un "m" in tutti i caratteri, ma la prima posizione del carattere prima della "m" finale in due stringhe. Solo una delle stringhe contiene la sottostringa necessaria. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce l'indice di "m" nella stringa quando esegue un confronto sensibile alle impostazioni cultura. Quando esegue un confronto ordinale, tuttavia, trova la sottostringa solo nella prima stringa. Si noti che nel caso della prima stringa, che include il trattino morbido seguito da un "m", il metodo non restituisce l'indice del trattino morbido, ma restituisce invece l'indice di "m" quando esegue un confronto sensibile alle impostazioni cultura. Il metodo restituisce l'indice del trattino morbido nella prima stringa solo quando esegue un confronto ordinale.

Imports System.Globalization

Public Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo

      Dim searchString As String = ChrW(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "m" 
      Dim s2 As String = "animal"
      Dim position As Integer

      position = ci.LastIndexOf(s1, "m"c)
      If position >= 1 Then
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, position, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, position, CompareOptions.Ordinal))
      End If      
      
      position = ci.LastIndexOf(s2, "m"c)
      If position >= 1 Then 
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, position, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, position, CompareOptions.Ordinal))
      End If
   End Sub
End Module
' The example displays the following output:
'       4
'       3
'       3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, String, Int32, CompareOptions)

Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato utilizzando il valore specificato CompareOptions .

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value, int startIndex, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, string value, int startIndex, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * string * int * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * string * int * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As String, startIndex As Integer, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

options: CompareOptions

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di value, se trovato, all'interno della sezione di source che si estende dall'inizio di a startIndex, usando le opzioni di source confronto specificate; in caso contrario, -1. Restituisce startIndex se value è un carattere ignorabile.

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una parte di una stringa. Si noti che IndexOf e LastIndexOf vengono eseguite ricerche in parti diverse della stringa, anche con lo stesso startIndex parametro.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 20;
      // myT1 is the string used for padding.
      String myT1;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

IndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : -------------------- as Æ or æ?
           AE :                         f
           ae :                              f
            Æ :                         f
            æ :                              f
Ordinal       : -------------------- as Æ or æ?
           AE :
           ae :
            Æ :                         f
            æ :                              f
IgnoreCase    : -------------------- as Æ or æ?
           AE :                         f
           ae :                         f
            Æ :                         f
            æ :                         f
LastIndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :    l
            æ :          l
Ordinal       : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :
            æ :
IgnoreCase    : Is AE or ae the same ----------
           AE :          l
           ae :          l
            Æ :          l
            æ :          l

IndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : -------------------- as Ü or ü?
           U" :                         f
           u" :                              f
            Ü :                         f
            ü :                              f
Ordinal       : -------------------- as Ü or ü?
           U" :
           u" :
            Ü :                         f
            ü :                              f
IgnoreCase    : -------------------- as Ü or ü?
           U" :                         f
           u" :                         f
            Ü :                         f
            ü :                         f
LastIndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :    l
            ü :          l
Ordinal       : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :
            ü :
IgnoreCase    : Is U" or u" the same ----------
           U" :          l
           u" :          l
            Ü :          l
            ü :          l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 20
      ' myT1 is the string used for padding.
      Dim myT1 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS]), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS]), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS]), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS]))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS]))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS]))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.Ordinal))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.Ordinal))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS]), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS]))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS]))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS]))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))
      
      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'IndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                              f
'            Æ :                         f
'            æ :                              f
'Ordinal       : -------------------- as Æ or æ?
'           AE :
'           ae :
'            Æ :                         f
'            æ :                              f
'IgnoreCase    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                         f
'            Æ :                         f
'            æ :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :    l
'            æ :          l
'Ordinal       : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :
'            æ :
'IgnoreCase    : Is AE or ae the same ----------
'           AE :          l
'           ae :          l
'            Æ :          l
'            æ :          l
'
'IndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                              f
'            Ü :                         f
'            ü :                              f
'Ordinal       : -------------------- as Ü or ü?
'           U" :
'           u" :
'            Ü :                         f
'            ü :                              f
'IgnoreCase    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                         f
'            Ü :                         f
'            ü :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :    l
'            ü :          l
'Ordinal       : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :
'            ü :
'IgnoreCase    : Is U" or u" the same ----------
'           U" :          l
'           u" :          l
'            Ü :          l
'            ü :          l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina all'inizio della stringa.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Annotazioni

Note per i chiamanti

Nell'esempio seguente il LastIndexOf(String, String, Int32, CompareOptions) metodo viene usato per trovare la posizione di un trattino morbido (U+00AD) seguito da un "m", a partire dall'ultimo "m" in due stringhe. Solo una delle stringhe contiene la sottostringa necessaria. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce l'indice di "m" nella stringa quando esegue un confronto sensibile alle impostazioni cultura. Si noti che nel caso della prima stringa, che include il trattino morbido seguito da un "m", il metodo non restituisce l'indice del trattino morbido, ma restituisce invece l'indice di "m". Il metodo restituisce l'indice del trattino morbido nella prima stringa solo quando esegue un confronto ordinale.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string searchString = "\u00ADm";
      string s1 = "ani\u00ADmal" ;
      string s2 = "animal";
      int position;

      position = ci.LastIndexOf(s1, 'm');
      if (position >= 0) {
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, CompareOptions.None));
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, CompareOptions.Ordinal));
      }

      position = ci.LastIndexOf(s2, 'm');
      if (position >= 0) {
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, CompareOptions.None));
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, CompareOptions.Ordinal));
      }
   }
}
// The example displays the following output:
//       4
//       3
//       3
//       -1

Imports System.Globalization

Public Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo

      Dim searchString As String = ChrW(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal" 
      Dim s2 As String = "animal"
      Dim position As Integer

      position = ci.LastIndexOf(s1, "m"c)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s1, searchString, position, CompareOptions.Ordinal))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, CompareOptions.None))
         Console.WriteLine(ci.LastIndexOf(s2, searchString, position, CompareOptions.Ordinal))
      End If
   End Sub
End Module
' The example displays the following output:
'       4
'       3
'       3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, Char, Int32, Int32)

Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine contenente il numero specificato di elementi e termina in corrispondenza dell'indice specificato.

public:
 virtual int LastIndexOf(System::String ^ source, char value, int startIndex, int count);

public virtual int LastIndexOf(string source, char value, int startIndex, int count);

abstract member LastIndexOf : string * char * int * int -> int
override this.LastIndexOf : string * char * int * int -> int

Public Overridable Function LastIndexOf (source As String, value As Char, startIndex As Integer, count As Integer) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

count: Int32

Numero di elementi nella sezione da cercare.

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di value, se trovato, all'interno della sezione di source che contiene il numero di elementi specificati da count e che termina in startIndex; in caso contrario, -1. Restituisce startIndex se value è un carattere ignorabile.

Eccezioni

ArgumentNullException

source è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

oppure

count è minore di zero.

oppure

startIndex e count non specificano una sezione valida in source.

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una parte di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 8;
      // iL is the length of the substring.
      int iL = 18;
      // myT1 and myT2 are the strings used for padding.
      String myT1 = new String( '-', iS );
      String myT2;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      myT2 = new String( '-', myStr.Length - iS - iL );
      Console.WriteLine();
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL ) );
      Console.WriteLine( "Ordinal       : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring( iS, iL ), myT2 );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, iL, CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', iS + iL - 1, iL, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

Original      : Is AE or ae the same as Æ or æ?
No options    : -------- ae the same as Æ -----
           AE :                         b
           ae :          b
            Æ :                         b
            æ :          b
Ordinal       : -------- ae the same as Æ -----
           AE :
           ae :          b
            Æ :                         b
            æ :
IgnoreCase    : -------- ae the same as Æ -----
           AE :          f              l
           ae :          f              l
            Æ :          f              l
            æ :          f              l

Original      : Is U" or u" the same as Ü or ü?
No options    : -------- u" the same as Ü -----
           U" :                         b
           u" :          b
            Ü :                         b
            ü :          b
Ordinal       : -------- u" the same as Ü -----
           U" :
           u" :          b
            Ü :                         b
            ü :
IgnoreCase    : -------- u" the same as Ü -----
           U" :          f              l
           u" :          f              l
            Ü :          f              l
            ü :          f              l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 8
      ' iL is the length of the substring.
      Dim iL As Integer = 18
      ' myT1 and myT2 are the strings used for padding.
      Dim myT1 As New [String]("-"c, [iS])
      Dim myT2 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      myT2 = New [String]("-"c, myStr.Length - [iS] - iL)
      Console.WriteLine()
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL))
      Console.WriteLine("Ordinal       : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}{2}", myT1, myStr.Substring([iS], iL), myT2)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], iL, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, [iS] + iL - 1, iL, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------- ae the same as Æ -----
'           AE :                         b
'           ae :          b
'            Æ :                         b
'            æ :          b
'Ordinal       : -------- ae the same as Æ -----
'           AE :
'           ae :          b
'            Æ :                         b
'            æ :
'IgnoreCase    : -------- ae the same as Æ -----
'           AE :          f              l
'           ae :          f              l
'            Æ :          f              l
'            æ :          f              l
'
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------- u" the same as Ü -----
'           U" :                         b
'           u" :          b
'            Ü :                         b
'            ü :          b
'Ordinal       : -------- u" the same as Ü -----
'           U" :
'           u" :          b
'            Ü :                         b
'            ü :
'IgnoreCase    : -------- u" the same as Ü -----
'           U" :          f              l
'           u" :          f              l
'            Ü :          f              l
'            ü :          f              l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina con startIndex - count + 1.

Questo overload esegue una ricerca sensibile alle impostazioni cultura. Se il carattere è un valore Unicode che rappresenta un carattere precomposto, ad esempio la legatura "Æ" (U+00C6), può essere considerata equivalente a qualsiasi occorrenza dei relativi componenti nella sequenza corretta, ad esempio "AE" (U+0041, U+0045), a seconda delle impostazioni cultura. Per eseguire una ricerca ordinale (senza distinzione tra impostazioni cultura), in cui un carattere viene considerato equivalente a un altro carattere solo se i valori Unicode sono uguali, è necessario chiamare uno degli overload con un parametro di tipo CompareOptions e usare il Ordinal valore . Gli overload di String.LastIndexOf tale ricerca di un carattere eseguono una ricerca ordinale, mentre quelli che cercano una stringa eseguono una ricerca sensibile alle impostazioni cultura.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char, Int32, Int32) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca. Nell'esempio seguente il LastIndexOf(String, Char, Int32, Int32) metodo viene usato per trovare un trattino morbido (U+00AD) che precede l'ultimo "m" in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce la posizione di indice di "m", ovvero il valore di startIndex.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      int position = 0;

      // Find the index of the soft hyphen.
      position = ci.IndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position, position + 1));

      position = ci.IndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position, position + 1));
   }
}
// The example displays the following output:
//       'm' at position 4
//       4
//       'm' at position 3
//       3

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim position As Integer
      Dim softHyphen As Char = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen.
      position = ci.IndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position, position + 1))
      End If
      
      position = ci.IndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position, position + 1))
      End If   
   End Sub
End Module
' The example displays the following output:
'       'm' at position 4
'       4
'       'm' at position 3
'       3

Vedi anche

IndexOf(String, Char)

Si applica a

LastIndexOf(String, Char, Int32, CompareOptions)

Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno della sezione della stringa di origine che si estende dall'inizio della stringa all'indice specificato utilizzando il valore specificato CompareOptions .

public:
 virtual int LastIndexOf(System::String ^ source, char value, int startIndex, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, char value, int startIndex, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * char * int * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * char * int * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As Char, startIndex As Integer, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

options: CompareOptions

Valori restituiti

Int32

Eccezioni

ArgumentNullException

source è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 20;
      // myT1 is the string used for padding.
      String myT1;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

IndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : -------------------- as Æ or æ?
           AE :                         f
           ae :                              f
            Æ :                         f
            æ :                              f
Ordinal       : -------------------- as Æ or æ?
           AE :
           ae :
            Æ :                         f
            æ :                              f
IgnoreCase    : -------------------- as Æ or æ?
           AE :                         f
           ae :                         f
            Æ :                         f
            æ :                         f
LastIndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :    l
            æ :          l
Ordinal       : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :
            æ :
IgnoreCase    : Is AE or ae the same ----------
           AE :          l
           ae :          l
            Æ :          l
            æ :          l

IndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : -------------------- as Ü or ü?
           U" :                         f
           u" :                              f
            Ü :                         f
            ü :                              f
Ordinal       : -------------------- as Ü or ü?
           U" :
           u" :
            Ü :                         f
            ü :                              f
IgnoreCase    : -------------------- as Ü or ü?
           U" :                         f
           u" :                         f
            Ü :                         f
            ü :                         f
LastIndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :    l
            ü :          l
Ordinal       : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :
            ü :
IgnoreCase    : Is U" or u" the same ----------
           U" :          l
           u" :          l
            Ü :          l
            ü :          l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 20
      ' myT1 is the string used for padding.
      Dim myT1 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS]), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS]), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS]), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS]))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS]))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS]))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.Ordinal))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.Ordinal))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS]), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS]))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS]))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS]))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))
      
      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'IndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                              f
'            Æ :                         f
'            æ :                              f
'Ordinal       : -------------------- as Æ or æ?
'           AE :
'           ae :
'            Æ :                         f
'            æ :                              f
'IgnoreCase    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                         f
'            Æ :                         f
'            æ :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :    l
'            æ :          l
'Ordinal       : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :
'            æ :
'IgnoreCase    : Is AE or ae the same ----------
'           AE :          l
'           ae :          l
'            Æ :          l
'            æ :          l
'
'IndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                              f
'            Ü :                         f
'            ü :                              f
'Ordinal       : -------------------- as Ü or ü?
'           U" :
'           u" :
'            Ü :                         f
'            ü :                              f
'IgnoreCase    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                         f
'            Ü :                         f
'            ü :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :    l
'            ü :          l
'Ordinal       : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :
'            ü :
'IgnoreCase    : Is U" or u" the same ----------
'           U" :          l
'           u" :          l
'            Ü :          l
'            ü :          l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina all'inizio della stringa.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char, Int32, CompareOptions) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca. Nell'esempio seguente il LastIndexOf(String, Char, Int32, CompareOptions) metodo viene usato per trovare un trattino morbido (U+00AD) che precede l'ultimo "m" in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, una ricerca sensibile alle impostazioni cultura restituisce la posizione di indice di "m". Una ricerca ordinale, tuttavia, trova correttamente il trattino morbido in una stringa e segnala che è assente dalla seconda stringa.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      int position = 0;

      // Find the index of the soft hyphen using culture-sensitive comparison.
      position = ci.LastIndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position, CompareOptions.IgnoreCase));

      position = ci.LastIndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position, CompareOptions.IgnoreCase));

      // Find the index of the soft hyphen using ordinal comparison.
      position = ci.LastIndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position, CompareOptions.Ordinal);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position, CompareOptions.Ordinal));

      position = ci.LastIndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position, CompareOptions.Ordinal);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position, CompareOptions.Ordinal));
   }
}
// The example displays the following output:
//       'm' at position 4
//       4
//       'm' at position 3
//       3
//       'm' at position 4
//       3
//       'm' at position 3
//       -1

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As Char = ChrW(&h00AD)
      Dim position As Integer
      
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen using culture-sensitive comparison.
      position = ci.LastIndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position, CompareOptions.IgnoreCase))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position, CompareOptions.IgnoreCase))
      End If  
       
      ' Find the index of the soft hyphen using ordinal comparison.
      position = ci.LastIndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position, CompareOptions.Ordinal))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position, CompareOptions.Ordinal))
      End If   
   End Sub
End Module
' The example displays the following output:
'       'm' at position 4
'       4
'       'm' at position 3
'       3
'       'm' at position 4
'       3
'       'm' at position 3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, Char, CompareOptions)

Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine usando il valore specificato CompareOptions .

public:
 virtual int LastIndexOf(System::String ^ source, char value, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, char value, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * char * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * char * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As Char, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

options: CompareOptions

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di , se trovato, all'interno sourcedi value, usando le opzioni di confronto specificate; in caso contrario, -1.

Eccezioni

ArgumentNullException

source è null.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE" ), myComp.LastIndexOf( myStr, "AE" ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae" ), myComp.LastIndexOf( myStr, "ae" ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ' ), myComp.LastIndexOf( myStr, 'Æ' ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ' ), myComp.LastIndexOf( myStr, 'æ' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308" ), myComp.LastIndexOf( myStr, "U\u0308" ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308" ), myComp.LastIndexOf( myStr, "u\u0308" ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü' ), myComp.LastIndexOf( myStr, 'Ü' ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü' ), myComp.LastIndexOf( myStr, 'ü' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c), myComp.LastIndexOf(myStr, "Æ"c))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c), myComp.LastIndexOf(myStr, "æ"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308)))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308)))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c), myComp.LastIndexOf(myStr, "Ü"c))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c), myComp.LastIndexOf(myStr, "ü"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 
         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'No options    : Is AE or ae the same as Æ or æ?
'           AE :    f                    l
'           ae :          f                   l
'            Æ :    f                    l
'            æ :          f                   l
'Ordinal       : Is AE or ae the same as Æ or æ?
'           AE :    b
'           ae :          b
'            Æ :                         b
'            æ :                              b
'IgnoreCase    : Is AE or ae the same as Æ or æ?
'           AE :    f                         l
'           ae :    f                         l
'            Æ :    f                         l
'            æ :    f                         l
'
'No options    : Is U" or u" the same as Ü or ü?
'           U" :    f                    l
'           u" :          f                   l
'            Ü :    f                    l
'            ü :          f                   l
'Ordinal       : Is U" or u" the same as Ü or ü?
'           U" :    b
'           u" :          b
'            Ü :                         b
'            ü :                              b
'IgnoreCase    : Is U" or u" the same as Ü or ü?
'           U" :    f                         l
'           u" :    f                         l
'            Ü :    f                         l
'            ü :    f                         l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire dalla fine della stringa e termina all'inizio della stringa.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char, CompareOptions) metodo restituisce sempre l'ultima posizione del carattere in source per indicare che la corrispondenza viene trovata alla fine di source. Nell'esempio seguente il LastIndexOf(String, Char, CompareOptions) metodo viene usato per cercare un trattino morbido (U+00AD) in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, una ricerca sensibile alle impostazioni cultura restituisce l'ultima posizione di indice nella stringa di origine. Al contrario, una ricerca ordinale trova correttamente il trattino morbido in una stringa e segnala che è assente dalla seconda stringa.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      // Find the last index of the soft hyphen using culture-sensitive comparison.
      Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', CompareOptions.IgnoreCase));
      Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', CompareOptions.IgnoreCase));

      // Find the last index of the soft hyphen using ordinal comparison.
      Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', CompareOptions.Ordinal));
      Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', CompareOptions.Ordinal));
   }
}
// The example displays the following output:
//       6
//       5
//       3
//       -1

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As Char = ChrW(&h00AD)
      
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the last index of the soft hyphen using culture-sensitive comparison.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen, CompareOptions.IgnoreCase))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen, CompareOptions.IgnoreCase))
      
      ' Find the last index of the soft hyphen using ordinal comparison.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen, CompareOptions.Ordinal))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen, CompareOptions.Ordinal))
   End Sub
End Module
' The example displays the following output:
'       6
'       5
'       3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, String, CompareOptions)

Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine usando il valore specificato CompareOptions .

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value, System::Globalization::CompareOptions options);

public virtual int LastIndexOf(string source, string value, System.Globalization.CompareOptions options);

abstract member LastIndexOf : string * string * System.Globalization.CompareOptions -> int
override this.LastIndexOf : string * string * System.Globalization.CompareOptions -> int

Public Overridable Function LastIndexOf (source As String, value As String, options As CompareOptions) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

options: CompareOptions

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di , se trovato, all'interno sourcedi value, usando le opzioni di confronto specificate; in caso contrario, -1.

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

ArgumentException

options contiene un valore non valido CompareOptions .

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE" ), myComp.LastIndexOf( myStr, "AE" ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae" ), myComp.LastIndexOf( myStr, "ae" ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ' ), myComp.LastIndexOf( myStr, 'Æ' ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ' ), myComp.LastIndexOf( myStr, 'æ' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308" ), myComp.LastIndexOf( myStr, "U\u0308" ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308" ), myComp.LastIndexOf( myStr, "u\u0308" ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü' ), myComp.LastIndexOf( myStr, 'Ü' ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü' ), myComp.LastIndexOf( myStr, 'ü' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c), myComp.LastIndexOf(myStr, "Æ"c))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c), myComp.LastIndexOf(myStr, "æ"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308)))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308)))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c), myComp.LastIndexOf(myStr, "Ü"c))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c), myComp.LastIndexOf(myStr, "ü"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 
         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'No options    : Is AE or ae the same as Æ or æ?
'           AE :    f                    l
'           ae :          f                   l
'            Æ :    f                    l
'            æ :          f                   l
'Ordinal       : Is AE or ae the same as Æ or æ?
'           AE :    b
'           ae :          b
'            Æ :                         b
'            æ :                              b
'IgnoreCase    : Is AE or ae the same as Æ or æ?
'           AE :    f                         l
'           ae :    f                         l
'            Æ :    f                         l
'            æ :    f                         l
'
'No options    : Is U" or u" the same as Ü or ü?
'           U" :    f                    l
'           u" :          f                   l
'            Ü :    f                    l
'            ü :          f                   l
'Ordinal       : Is U" or u" the same as Ü or ü?
'           U" :    b
'           u" :          b
'            Ü :                         b
'            ü :                              b
'IgnoreCase    : Is U" or u" the same as Ü or ü?
'           U" :    f                         l
'           u" :    f                         l
'            Ü :    f                         l
'            ü :    f                         l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire dalla fine della stringa e termina all'inizio della stringa.

I CompareOptions.NumericOrdering valori e CompareOptions.StringSort non sono validi per questo metodo.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, ovvero se options non Ordinal è o OrdinalIgnoreCase, se value contiene un carattere ignorabile, il risultato equivale alla ricerca con il carattere rimosso. Se value è costituito solo da uno o più caratteri ignorabili, il LastIndexOf(String, String, CompareOptions) metodo restituisce sourcesempre .Length - 1, che rappresenta l'ultima posizione dell'indice in source. Nell'esempio seguente il LastIndexOf(String, String, CompareOptions) metodo viene usato per trovare tre sottostringhe (un trattino morbido (U+00AD), un trattino morbido seguito da "n" e un trattino morbido seguito da "m") in due stringhe. Solo una delle stringhe contiene un trattino morbido. Poiché il trattino morbido è un carattere ignorabile, una ricerca sensibile alle impostazioni cultura restituisce lo stesso valore restituito se il trattino morbido non fosse incluso nella stringa di ricerca. Una ricerca ordinale, tuttavia, trova correttamente il trattino morbido in una stringa e segnala che è assente dalla seconda stringa.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      Console.WriteLine("Culture-sensitive comparison:");
      // Use culture-sensitive comparison to find the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, "\u00AD", CompareOptions.None));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00AD", CompareOptions.None));

      // Use culture-sensitive comparison to find the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADn", CompareOptions.None));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADn", CompareOptions.None));

      // Use culture-sensitive comparison to find the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADm", CompareOptions.None));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADm", CompareOptions.None));

      Console.WriteLine("Ordinal comparison:");
      // Use ordinal comparison to find the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, "\u00AD", CompareOptions.Ordinal));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00AD", CompareOptions.Ordinal));

      // Use ordinal comparison to find the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADn", CompareOptions.Ordinal));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADn", CompareOptions.Ordinal));

      // Use ordinal comparison to find the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADm", CompareOptions.Ordinal));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADm", CompareOptions.Ordinal));
   }
}
// The example displays the following output:
//       6
//       5
//       1
//       1
//       4
//       3
//       Ordinal comparison:
//       3
//       -1
//       -1
//       -1
//       3
//       -1

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As String = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      Console.WriteLine("Culture-sensitive comparison:")
      ' Use culture-sensitive comparison to find the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen, CompareOptions.None))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen, CompareOptions.None))
      
      ' Use culture-sensitive comparison to find the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "n", CompareOptions.None))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "n", CompareOptions.None))
      
      ' Use culture-sensitive comparison to find the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "m", CompareOptions.None))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "m", CompareOptions.None))
      
      Console.WriteLine("Ordinal comparison:")
      ' Use ordinal comparison to find the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen, CompareOptions.Ordinal))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen, CompareOptions.Ordinal))
      
      ' Use ordinal comparison to find the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "n", CompareOptions.Ordinal))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "n", CompareOptions.Ordinal))
      
      ' Use ordinal comparison to find the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "m", CompareOptions.Ordinal))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "m", CompareOptions.Ordinal))
   End Sub
End Module
' The example displays the following output:
'       6
'       5
'       1
'       1
'       4
'       3
'       Ordinal comparison:
'       3
'       -1
'       -1
'       -1
'       3
'       -1

Vedi anche

Si applica a

LastIndexOf(String, Char, Int32)

public:
 virtual int LastIndexOf(System::String ^ source, char value, int startIndex);

public virtual int LastIndexOf(string source, char value, int startIndex);

abstract member LastIndexOf : string * char * int -> int
override this.LastIndexOf : string * char * int -> int

Public Overridable Function LastIndexOf (source As String, value As Char, startIndex As Integer) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di value, se trovato, all'interno della sezione di source che si estende dall'inizio di source a startIndex; in caso contrario, -1. Restituisce startIndex se value è un carattere ignorabile.

Eccezioni

ArgumentNullException

source è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

Esempio

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 20;
      // myT1 is the string used for padding.
      String myT1;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

IndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : -------------------- as Æ or æ?
           AE :                         f
           ae :                              f
            Æ :                         f
            æ :                              f
Ordinal       : -------------------- as Æ or æ?
           AE :
           ae :
            Æ :                         f
            æ :                              f
IgnoreCase    : -------------------- as Æ or æ?
           AE :                         f
           ae :                         f
            Æ :                         f
            æ :                         f
LastIndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :    l
            æ :          l
Ordinal       : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :
            æ :
IgnoreCase    : Is AE or ae the same ----------
           AE :          l
           ae :          l
            Æ :          l
            æ :          l

IndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : -------------------- as Ü or ü?
           U" :                         f
           u" :                              f
            Ü :                         f
            ü :                              f
Ordinal       : -------------------- as Ü or ü?
           U" :
           u" :
            Ü :                         f
            ü :                              f
IgnoreCase    : -------------------- as Ü or ü?
           U" :                         f
           u" :                         f
            Ü :                         f
            ü :                         f
LastIndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :    l
            ü :          l
Ordinal       : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :
            ü :
IgnoreCase    : Is U" or u" the same ----------
           U" :          l
           u" :          l
            Ü :          l
            ü :          l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 20
      ' myT1 is the string used for padding.
      Dim myT1 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS]), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS]), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS]), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS]))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS]))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS]))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.Ordinal))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.Ordinal))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS]), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS]))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS]))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS]))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))
      
      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'IndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                              f
'            Æ :                         f
'            æ :                              f
'Ordinal       : -------------------- as Æ or æ?
'           AE :
'           ae :
'            Æ :                         f
'            æ :                              f
'IgnoreCase    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                         f
'            Æ :                         f
'            æ :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :    l
'            æ :          l
'Ordinal       : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :
'            æ :
'IgnoreCase    : Is AE or ae the same ----------
'           AE :          l
'           ae :          l
'            Æ :          l
'            æ :          l
'
'IndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                              f
'            Ü :                         f
'            ü :                              f
'Ordinal       : -------------------- as Ü or ü?
'           U" :
'           u" :
'            Ü :                         f
'            ü :                              f
'IgnoreCase    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                         f
'            Ü :                         f
'            ü :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :    l
'            ü :          l
'Ordinal       : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :
'            ü :
'IgnoreCase    : Is U" or u" the same ----------
'           U" :          l
'           u" :          l
'            Ü :          l
'            ü :          l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina all'inizio della stringa.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char, Int32) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca. Nell'esempio seguente il LastIndexOf(String, Char, Int32) metodo viene usato per trovare un trattino morbido (U+00AD) che precede l'ultimo "m" in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce la posizione di indice di "m", ovvero il valore di startIndex.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      int position = 0;

      // Find the last index of the soft hyphen.
      position = ci.LastIndexOf(s1, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, '\u00AD', position));

      position = ci.LastIndexOf(s2, 'm');
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, '\u00AD', position));
   }
}
// The example displays the following output:
//       'm' at position 4
//       4
//       'm' at position 3

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim position As Integer
      Dim softHyphen As Char = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the last index of the soft hyphen.
      position = ci.LastIndexOf(s1, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position))
      End If
      
      position = ci.LastIndexOf(s2, "m"c)
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position))
      End If   
   End Sub
End Module
' The example displays the following output:
'       'm' at position 4
'       4
'       'm' at position 3
'       3

Vedi anche

IndexOf(String, Char)

Si applica a

LastIndexOf(String, String)

Cerca la sottostringa specificata e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine.

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value);

public virtual int LastIndexOf(string source, string value);

abstract member LastIndexOf : string * string -> int
override this.LastIndexOf : string * string -> int

Public Overridable Function LastIndexOf (source As String, value As String) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di , se trovato, all'interno sourcedi value; in caso contrario, -1.

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE" ), myComp.LastIndexOf( myStr, "AE" ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae" ), myComp.LastIndexOf( myStr, "ae" ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ' ), myComp.LastIndexOf( myStr, 'Æ' ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ' ), myComp.LastIndexOf( myStr, 'æ' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308" ), myComp.LastIndexOf( myStr, "U\u0308" ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308" ), myComp.LastIndexOf( myStr, "u\u0308" ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü' ), myComp.LastIndexOf( myStr, 'Ü' ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü' ), myComp.LastIndexOf( myStr, 'ü' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c), myComp.LastIndexOf(myStr, "Æ"c))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c), myComp.LastIndexOf(myStr, "æ"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308)))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308)))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c), myComp.LastIndexOf(myStr, "Ü"c))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c), myComp.LastIndexOf(myStr, "ü"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 
         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'No options    : Is AE or ae the same as Æ or æ?
'           AE :    f                    l
'           ae :          f                   l
'            Æ :    f                    l
'            æ :          f                   l
'Ordinal       : Is AE or ae the same as Æ or æ?
'           AE :    b
'           ae :          b
'            Æ :                         b
'            æ :                              b
'IgnoreCase    : Is AE or ae the same as Æ or æ?
'           AE :    f                         l
'           ae :    f                         l
'            Æ :    f                         l
'            æ :    f                         l
'
'No options    : Is U" or u" the same as Ü or ü?
'           U" :    f                    l
'           u" :          f                   l
'            Ü :    f                    l
'            ü :          f                   l
'Ordinal       : Is U" or u" the same as Ü or ü?
'           U" :    b
'           u" :          b
'            Ü :                         b
'            ü :                              b
'IgnoreCase    : Is U" or u" the same as Ü or ü?
'           U" :    f                         l
'           u" :    f                         l
'            Ü :    f                         l
'            ü :    f                         l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire dalla fine della stringa e termina all'inizio della stringa.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value contiene un carattere ignorabile, il risultato equivale alla ricerca con tale carattere rimosso. Se value è costituito solo da uno o più caratteri ignorabili, il LastIndexOf(String, String) metodo restituisce sourcesempre .Length - 1, che rappresenta l'ultima posizione dell'indice in source. Nell'esempio seguente il LastIndexOf(String, String) metodo viene usato per trovare tre sottostringhe (un trattino morbido (U+00AD), un trattino morbido seguito da "n" e un trattino morbido seguito da "m") in due stringhe. Solo una delle stringhe contiene un trattino morbido. In ogni caso, poiché il trattino morbido è un carattere ignorabile, il risultato è uguale a se il trattino morbido non fosse stato incluso in value. Quando si cerca solo un trattino morbido, il metodo restituisce 6 e 5. Questi valori corrispondono all'indice dell'ultimo carattere nelle due stringhe.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      // Find the index of the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, "\u00AD"));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00AD"));

      // Find the index of the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADn"));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADn"));

      // Find the index of the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, "\u00ADm"));
      Console.WriteLine(ci.LastIndexOf(s2, "\u00ADm"));
   }
}
// The example displays the following output:
//       6
//       5
//       1
//       1
//       4
//       3

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As String = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen))
      
      ' Find the index of the last soft hyphen followed by "n".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "n"))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "n"))
      
      ' Find the index of the last soft hyphen followed by "m".
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "m"))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "m"))
   End Sub
End Module
' The example displays the following output:
'       6
'       5
'       1
'       1
'       4
'       3

Vedi anche

IndexOf(String, Char)

Si applica a

LastIndexOf(String, Char)

Cerca il carattere specificato e restituisce l'indice in base zero dell'ultima occorrenza all'interno dell'intera stringa di origine.

public:
 virtual int LastIndexOf(System::String ^ source, char value);

public virtual int LastIndexOf(string source, char value);

abstract member LastIndexOf : string * char -> int
override this.LastIndexOf : string * char -> int

Public Overridable Function LastIndexOf (source As String, value As Char) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: Char

Carattere da individuare all'interno sourcedi .

Valori restituiti

Int32

Indice in base zero dell'ultima occorrenza di , se trovato, all'interno sourcedi value; in caso contrario, -1.

Eccezioni

ArgumentNullException

source è null.

Esempio

L'esempio seguente determina gli indici della prima e dell'ultima occorrenza di un carattere o di una sottostringa all'interno di una stringa.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE" ), myComp.LastIndexOf( myStr, "AE" ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae" ), myComp.LastIndexOf( myStr, "ae" ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ' ), myComp.LastIndexOf( myStr, 'Æ' ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ' ), myComp.LastIndexOf( myStr, 'æ' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308" ), myComp.LastIndexOf( myStr, "U\u0308" ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308" ), myComp.LastIndexOf( myStr, "u\u0308" ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü' ), myComp.LastIndexOf( myStr, 'Ü' ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü' ), myComp.LastIndexOf( myStr, 'ü' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c), myComp.LastIndexOf(myStr, "Æ"c))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c), myComp.LastIndexOf(myStr, "æ"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.Ordinal))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()
      Console.WriteLine("No options    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308)))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308)), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308)))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c), myComp.LastIndexOf(myStr, "Ü"c))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c), myComp.LastIndexOf(myStr, "ü"c))
      Console.WriteLine("Ordinal       : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.Ordinal))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.Ordinal))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}", myStr)
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 
         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))

      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'No options    : Is AE or ae the same as Æ or æ?
'           AE :    f                    l
'           ae :          f                   l
'            Æ :    f                    l
'            æ :          f                   l
'Ordinal       : Is AE or ae the same as Æ or æ?
'           AE :    b
'           ae :          b
'            Æ :                         b
'            æ :                              b
'IgnoreCase    : Is AE or ae the same as Æ or æ?
'           AE :    f                         l
'           ae :    f                         l
'            Æ :    f                         l
'            æ :    f                         l
'
'No options    : Is U" or u" the same as Ü or ü?
'           U" :    f                    l
'           u" :          f                   l
'            Ü :    f                    l
'            ü :          f                   l
'Ordinal       : Is U" or u" the same as Ü or ü?
'           U" :    b
'           u" :          b
'            Ü :                         b
'            ü :                              b
'IgnoreCase    : Is U" or u" the same as Ü or ü?
'           U" :    f                         l
'           u" :    f                         l
'            Ü :    f                         l
'            ü :    f                         l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire dalla fine della stringa e termina all'inizio della stringa.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value è un carattere ignorabile, il risultato equivale alla ricerca con quel carattere rimosso. In questo caso, il LastIndexOf(String, Char) metodo restituisce sempre l'ultima posizione di indice in source per indicare che la corrispondenza viene trovata alla fine di source. Nell'esempio seguente il LastIndexOf(String, Char) metodo viene usato per trovare il trattino morbido (U+00AD) in due stringhe. Solo una delle stringhe contiene un trattino morbido. In entrambi i casi, poiché il trattino morbido è un carattere ignorabile, il metodo restituisce l'ultima posizione di indice nella stringa per indicare che ha trovato una corrispondenza alla fine della stringa.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      // Find the index of the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, '\u00AD'));
      Console.WriteLine(ci.LastIndexOf(s2, '\u00AD'));
   }
}
// The example displays the following output:
//       6
//       5

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim softHyphen As Char = ChrW(&h00AD)
      
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the last soft hyphen.
      Console.WriteLine(ci.LastIndexOf(s1, softHyphen))
      Console.WriteLine(ci.LastIndexOf(s2, softHyphen))
   End Sub
End Module
' The example displays the following output:
'       6
'       5

Vedi anche

IndexOf(String, Char)

Si applica a

LastIndexOf(String, String, Int32)

public:
 virtual int LastIndexOf(System::String ^ source, System::String ^ value, int startIndex);

public virtual int LastIndexOf(string source, string value, int startIndex);

abstract member LastIndexOf : string * string * int -> int
override this.LastIndexOf : string * string * int -> int

Public Overridable Function LastIndexOf (source As String, value As String, startIndex As Integer) As Integer

Parametri

source: String

Stringa in cui effettuare la ricerca.

value: String

Stringa da individuare all'interno sourcedi .

startIndex: Int32

Indice iniziale in base zero della ricerca all'indietro.

Valori restituiti

Int32

Eccezioni

ArgumentNullException

source è null.

oppure

value è null.

ArgumentOutOfRangeException

startIndex non è compreso nell'intervallo di indici validi per source.

Esempio

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // iS is the starting index of the substring.
      int iS = 20;
      // myT1 is the string used for padding.
      String myT1;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           AE : ", -1, myComp.LastIndexOf( myStr, "AE", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", -1, myComp.LastIndexOf( myStr, "ae", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", -1, myComp.LastIndexOf( myStr, 'Æ', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", -1, myComp.LastIndexOf( myStr, 'æ', iS, CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();

      myT1 = new String( '-', iS );
      Console.WriteLine( "IndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS ), -1 );
      Console.WriteLine( "Ordinal       : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ), -1 );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myT1, myStr.Substring( iS ) );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ), -1 );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ), -1 );

      myT1 = new String( '-', myStr.Length - iS - 1 );
      Console.WriteLine( "LastIndexOf( String, *, {0}, * )", iS );
      Console.WriteLine( "Original      : {0}", myStr );
      Console.WriteLine( "No options    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS ) );
      Console.WriteLine( "Ordinal       : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}{1}", myStr.Substring( 0, iS + 1 ), myT1 );
      PrintMarker( "           U\u0308 : ", -1, myComp.LastIndexOf( myStr, "U\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", -1, myComp.LastIndexOf( myStr, "u\u0308", iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", -1, myComp.LastIndexOf( myStr, 'Ü', iS, CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", -1, myComp.LastIndexOf( myStr, 'ü', iS, CompareOptions.IgnoreCase ) );
   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create.
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers.
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );
      }
      else
        {
            Console.WriteLine( Prefix );
        }
    }
}


/*
This code produces the following output.

IndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : -------------------- as Æ or æ?
           AE :                         f
           ae :                              f
            Æ :                         f
            æ :                              f
Ordinal       : -------------------- as Æ or æ?
           AE :
           ae :
            Æ :                         f
            æ :                              f
IgnoreCase    : -------------------- as Æ or æ?
           AE :                         f
           ae :                         f
            Æ :                         f
            æ :                         f
LastIndexOf( String, *, 20, * )
Original      : Is AE or ae the same as Æ or æ?
No options    : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :    l
            æ :          l
Ordinal       : Is AE or ae the same ----------
           AE :    l
           ae :          l
            Æ :
            æ :
IgnoreCase    : Is AE or ae the same ----------
           AE :          l
           ae :          l
            Æ :          l
            æ :          l

IndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : -------------------- as Ü or ü?
           U" :                         f
           u" :                              f
            Ü :                         f
            ü :                              f
Ordinal       : -------------------- as Ü or ü?
           U" :
           u" :
            Ü :                         f
            ü :                              f
IgnoreCase    : -------------------- as Ü or ü?
           U" :                         f
           u" :                         f
            Ü :                         f
            ü :                         f
LastIndexOf( String, *, 20, * )
Original      : Is U" or u" the same as Ü or ü?
No options    : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :    l
            ü :          l
Ordinal       : Is U" or u" the same ----------
           U" :    l
           u" :          l
            Ü :
            ü :
IgnoreCase    : Is U" or u" the same ----------
           U" :          l
           u" :          l
            Ü :          l
            ü :          l

*/

Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' iS is the starting index of the substring.
      Dim [iS] As Integer = 20
      ' myT1 is the string used for padding.
      Dim myT1 As [String]

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS]), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS]), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS]), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           AE : ", myComp.IndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           ae : ", myComp.IndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Æ : ", myComp.IndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            æ : ", myComp.IndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS]))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS]))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS]))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.Ordinal))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.Ordinal))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           AE : ", - 1, myComp.LastIndexOf(myStr, "AE", [iS], CompareOptions.IgnoreCase))
      PrintMarker("           ae : ", - 1, myComp.LastIndexOf(myStr, "ae", [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Æ : ", - 1, myComp.LastIndexOf(myStr, "Æ"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            æ : ", - 1, myComp.LastIndexOf(myStr, "æ"c, [iS], CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H0055) & ChrW(&H0308) & " or " & ChrW(&H0075) & ChrW(&H0308) & " the same as " & ChrW(&H00DC) & " or " & ChrW(&H00FC) & "?"
      Console.WriteLine()

      myT1 = New [String]("-"c, [iS])
      Console.WriteLine("IndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS]), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS]), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS]), - 1)
      Console.WriteLine("Ordinal       : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal), - 1)
      Console.WriteLine("IgnoreCase    : {0}{1}", myT1, myStr.Substring([iS]))
      PrintMarker("           U" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("           u" & ChrW(&H0308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            Ü : ", myComp.IndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase), - 1)
      PrintMarker("            ü : ", myComp.IndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase), - 1)

      myT1 = New [String]("-"c, myStr.Length - [iS] - 1)
      Console.WriteLine("LastIndexOf( String, *, {0}, * )", [iS])
      Console.WriteLine("Original      : {0}", myStr)
      Console.WriteLine("No options    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS]))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS]))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS]))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS]))
      Console.WriteLine("Ordinal       : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.Ordinal))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.Ordinal))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.Ordinal))
      Console.WriteLine("IgnoreCase    : {0}{1}", myStr.Substring(0, [iS] + 1), myT1)
      PrintMarker("           U" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "U" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("           u" & ChrW(&H0308) & " : ", - 1, myComp.LastIndexOf(myStr, "u" & ChrW(&H0308), [iS], CompareOptions.IgnoreCase))
      PrintMarker("            Ü : ", - 1, myComp.LastIndexOf(myStr, "Ü"c, [iS], CompareOptions.IgnoreCase))
      PrintMarker("            ü : ", - 1, myComp.LastIndexOf(myStr, "ü"c, [iS], CompareOptions.IgnoreCase))

   End Sub

   Public Shared Sub PrintMarker(Prefix As [String], First As Integer, Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If 

      If mySize > - 1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > - 1 Then
            myCharArr(First) = "f"c
         End If
         If Last > - 1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If 

         ' Displays the array of Char as a String.
         Console.WriteLine("{0}{1}", Prefix, New [String](myCharArr))
      
      Else
         Console.WriteLine(Prefix)

      End If 

   End Sub

End Class


'This code produces the following output.
'
'IndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                              f
'            Æ :                         f
'            æ :                              f
'Ordinal       : -------------------- as Æ or æ?
'           AE :
'           ae :
'            Æ :                         f
'            æ :                              f
'IgnoreCase    : -------------------- as Æ or æ?
'           AE :                         f
'           ae :                         f
'            Æ :                         f
'            æ :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is AE or ae the same as Æ or æ?
'No options    : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :    l
'            æ :          l
'Ordinal       : Is AE or ae the same ----------
'           AE :    l
'           ae :          l
'            Æ :
'            æ :
'IgnoreCase    : Is AE or ae the same ----------
'           AE :          l
'           ae :          l
'            Æ :          l
'            æ :          l
'
'IndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                              f
'            Ü :                         f
'            ü :                              f
'Ordinal       : -------------------- as Ü or ü?
'           U" :
'           u" :
'            Ü :                         f
'            ü :                              f
'IgnoreCase    : -------------------- as Ü or ü?
'           U" :                         f
'           u" :                         f
'            Ü :                         f
'            ü :                         f
'LastIndexOf( String, *, 20, * )
'Original      : Is U" or u" the same as Ü or ü?
'No options    : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :    l
'            ü :          l
'Ordinal       : Is U" or u" the same ----------
'           U" :    l
'           u" :          l
'            Ü :
'            ü :
'IgnoreCase    : Is U" or u" the same ----------
'           U" :          l
'           u" :          l
'            Ü :          l
'            ü :          l

Commenti

La stringa di origine viene eseguita una ricerca all'indietro a partire da startIndex e termina all'inizio della stringa.

Annotazioni

Note per i chiamanti

I set di caratteri includono caratteri ignorabili, che sono caratteri non considerati durante l'esecuzione di un ordinamento linguistico o sensibile alle impostazioni cultura. In una ricerca sensibile alle impostazioni cultura, se value contiene un carattere ignorabile, il risultato equivale alla ricerca con tale carattere rimosso. Se value è costituito solo da uno o più caratteri ignorabili, il LastIndexOf(String, String, Int32) metodo restituisce startIndexsempre , ovvero la posizione del carattere in corrispondenza della quale inizia la ricerca. Nell'esempio seguente il LastIndexOf(String, String, Int32) metodo viene usato per trovare una sottostringa che include un trattino morbido (U+00AD) e che precede o include l'ultimo "m" in una stringa. Poiché il trattino morbido nella stringa di ricerca viene ignorato, la chiamata al metodo per trovare una sottostringa costituita dal trattino morbido e "m" restituisce la posizione di "m" nella stringa, mentre chiamandola per trovare una sottostringa costituita dal trattino morbido e "n" restituisce la posizione di "n". Quando la stringa di ricerca contiene solo il trattino morbido, il metodo restituisce l'indice di "m", che rappresenta il valore di startIndex.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      CompareInfo ci = CultureInfo.CurrentCulture.CompareInfo;

      int position = 0;

      string s1 = "ani\u00ADmal";
      string s2 = "animal";

      // Find the index of the soft hyphen.
      position = ci.LastIndexOf(s1, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, "\u00AD", position));

      position = ci.LastIndexOf(s2, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, "\u00AD", position));

      // Find the index of the soft hyphen followed by "n".
      position = ci.LastIndexOf(s1, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, "\u00ADn", position));

      position = ci.LastIndexOf(s2, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, "\u00ADn", position));

      // Find the index of the soft hyphen followed by "m".
      position = ci.LastIndexOf(s1, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s1, "\u00ADm", position));

      position = ci.LastIndexOf(s2, "m");
      Console.WriteLine("'m' at position {0}", position);
      if (position >= 0)
         Console.WriteLine(ci.LastIndexOf(s2, "\u00ADm", position));
   }
}
// The example displays the following output:
//       'm' at position 4
//       4
//       'm' at position 3
//       3
//       'm' at position 4
//       1
//       'm' at position 3
//       1
//       'm' at position 4
//       4
//       'm' at position 3
//       3

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      
      Dim position As Integer
      Dim softHyphen As String = ChrW(&h00AD)
      
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen.
      position = ci.LastIndexOf(s1, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen, position))
      End If
         
      position = ci.LastIndexOf(s2, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen, position))
      End If
      
      ' Find the index of the soft hyphen followed by "n".
      position = ci.LastIndexOf(s1, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "n", position))
      End If
         
      position = ci.LastIndexOf(s2, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "n", position))
      End If
      
      ' Find the index of the soft hyphen followed by "m".
      position = ci.LastIndexOf(s1, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s1, softHyphen + "m", position))
      End If
      
      position = ci.LastIndexOf(s2, "m")
      Console.WriteLine("'m' at position {0}", position)
      If position >= 0 Then
         Console.WriteLine(ci.LastIndexOf(s2, softHyphen + "m", position))
      End If
   End Sub
End Module
' The example displays the following output:
'       'm' at position 4
'       4
'       'm' at position 3
'       3
'       'm' at position 4
'       1
'       'm' at position 3
'       1
'       'm' at position 4
'       4
'       'm' at position 3
'       3

Vedi anche

IndexOf(String, Char)

Si applica a

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