Convert.ToByte Methode

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public:
 static System::Byte ToByte(System::String ^ value);

public static byte ToByte(string value);

public static byte ToByte(string? value);

static member ToByte : string -> byte

Public Shared Function ToByte (value As String) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value, of nul als value dat is null.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een tekenreeksmatrix gedefinieerd en wordt geprobeerd elke tekenreeks te converteren naar een Byte. Houd er rekening mee dat terwijl een null tekenreeks naar nul parseert, String.Empty een FormatException. Houd er ook rekening mee dat tijdens het parseren van voorloop- en volgspaties, het opmaken van symbolen, zoals valutasymbolen, groepsscheidingstekens of scheidingstekens voor decimalen, dit niet doet.

using System;

public class Example
{
   public static void Main()
   {
      String[] values = { null, "", "0xC9", "C9", "101", "16.3",
                          "$12", "$12.01", "-4", "1,032", "255",
                          "   16  " };
      foreach (var value in values) {
         try {
            byte number = Convert.ToByte(value);
            Console.WriteLine("'{0}' --> {1}",
                              value == null ? "<null>" : value, number);
         }
         catch (FormatException) {
            Console.WriteLine("Bad Format: '{0}'",
                              value == null ? "<null>" : value);
         }
         catch (OverflowException) {
            Console.WriteLine("OverflowException: '{0}'", value);
         }
      }
   }
}
// The example displays the following output:
//     '<null>' --> 0
//     Bad Format: ''
//     Bad Format: '0xC9'
//     Bad Format: 'C9'
//     '101' --> 101
//     Bad Format: '16.3'
//     Bad Format: '$12'
//     Bad Format: '$12.01'
//     OverflowException: '-4'
//     Bad Format: '1,032'
//     '255' --> 255
//     '   16  ' --> 16

open System

let values = 
    [| null; ""; "0xC9"; "C9"; "101"; "16.3"; "$12"
       "$12.01"; "-4"; "1,032"; "255"; "   16  " |]

for value in values do
    try
        let number = Convert.ToByte(value)
        printfn $"""'%A{value}' --> {number}"""
    with
    | :? FormatException ->
        printfn $"Bad Format: '%A{value}'"
    | :? OverflowException ->
        printfn $"OverflowException: '{value}'"
        
// The example displays the following output:
//     '<null>' --> 0
//     Bad Format: ''
//     Bad Format: '0xC9'
//     Bad Format: 'C9'
//     '101' --> 101
//     Bad Format: '16.3'
//     Bad Format: '$12'
//     Bad Format: '$12.01'
//     OverflowException: '-4'
//     Bad Format: '1,032'
//     '255' --> 255
//     '   16  ' --> 16

Module Example
   Public Sub Main()
      Dim values() As String = { Nothing, "", "0xC9", "C9", "101", 
                                 "16.3", "$12", "$12.01", "-4", 
                                 "1,032", "255", "   16  " }
      For Each value In values
         Try 
            Dim number As Byte = Convert.ToByte(value)
            Console.WriteLine("'{0}' --> {1}", 
                              If(value Is Nothing, "<null>", value), number)
         Catch e As FormatException
            Console.WriteLine("Bad Format: '{0}'", 
                              If(value Is Nothing, "<null>", value))
         Catch e As OverflowException
            Console.WriteLine("OverflowException: '{0}'", value)
         End Try
      Next
   End Sub
End Module
' The example displays the following output:
'     '<null>' --> 0
'     Bad Format: ''
'     Bad Format: '0xC9'
'     Bad Format: 'C9'
'     '101' --> 101
'     Bad Format: '16.3'
'     Bad Format: '$12'
'     Bad Format: '$12.01'
'     OverflowException: '-4'
'     Bad Format: '1,032'
'     '255' --> 255
'     '   16  ' --> 16

Opmerkingen

Het gebruik van de ToByte(String) methode is gelijk aan het doorgeven value aan de Byte.Parse(String) methode. value wordt geïnterpreteerd met behulp van de opmaakconventies van de huidige cultuur.

Als u liever geen uitzondering afhandelt als de conversie mislukt, kunt u in plaats daarvan de Byte.TryParse methode aanroepen. Het retourneert een Boolean waarde die aangeeft of de conversie is geslaagd of mislukt.

Zie ook

• Parse(String)

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public:
 static System::Byte ToByte(System::UInt16 value);

[System.CLSCompliant(false)]
public static byte ToByte(ushort value);

[<System.CLSCompliant(false)>]
static member ToByte : uint16 -> byte

Public Shared Function ToByte (value As UShort) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Kenmerken

CLSCompliantAttribute

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met niet-ondertekende 16-bits gehele getallen geconverteerd naar Byte waarden.

ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
byte result;
foreach (ushort number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt16 value 0 to the Byte value 0.
//       Converted the UInt16 value 121 to the Byte value 121.
//       The UInt16 value 340 is outside the range of the Byte type.
//       The UInt16 value 65535 is outside the range of the Byte type.

let numbers = [| UInt16.MinValue; 121us; 340us; UInt16.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       Converted the UInt16 value 0 to the Byte value 0.
//       Converted the UInt16 value 121 to the Byte value 121.
//       The UInt16 value 340 is outside the range of the Byte type.
//       The UInt16 value 65535 is outside the range of the Byte type.

Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As Byte
For Each number As UShort In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt16 value 0 to the Byte value 0.
'       Converted the UInt16 value 121 to the Byte value 121.
'       The UInt16 value 340 is outside the range of the Byte type.
'       The UInt16 value 65535 is outside the range of the Byte type.

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public:
 static System::Byte ToByte(System::UInt32 value);

[System.CLSCompliant(false)]
public static byte ToByte(uint value);

[<System.CLSCompliant(false)>]
static member ToByte : uint32 -> byte

Public Shared Function ToByte (value As UInteger) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Kenmerken

CLSCompliantAttribute

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met niet-ondertekende gehele getallen geconverteerd naar Byte waarden.

uint[] numbers = { UInt32.MinValue, 121, 340, UInt32.MaxValue };
byte result;
foreach (uint number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt32 value 0 to the Byte value 0.
//       Converted the UInt32 value 121 to the Byte value 121.
//       The UInt32 value 340 is outside the range of the Byte type.
//       The UInt32 value 4294967295 is outside the range of the Byte type.

let numbers = [| UInt32.MinValue; 121u; 340u; UInt32.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       Converted the UInt32 value 0 to the Byte value 0.
//       Converted the UInt32 value 121 to the Byte value 121.
//       The UInt32 value 340 is outside the range of the Byte type.
//       The UInt32 value 4294967295 is outside the range of the Byte type.

Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As Byte
For Each number As UInteger In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt32 value 0 to the Byte value 0.
'       Converted the UInt32 value 121 to the Byte value 121.
'       The UInt32 value 340 is outside the range of the Byte type.
'       The UInt32 value 4294967295 is outside the range of the Byte type.

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public:
 static System::Byte ToByte(System::String ^ value, int fromBase);

public static byte ToByte(string value, int fromBase);

public static byte ToByte(string? value, int fromBase);

static member ToByte : string * int -> byte

Public Shared Function ToByte (value As String, fromBase As Integer) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan het getal in value, of 0 (nul) als value dat is null.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt ook geprobeerd een matrix met tekenreeksen te interpreteren als de weergave van binaire, octale, decimale en hexadecimale waarden.

using System;

public class Example
{
   public static void Main()
   {
      int[] bases = { 2, 8, 10, 16 };
      string[] values = { "-1", "1", "08", "0F", "11" , "12", "30",
                          "101", "255", "FF", "10000000", "80" };
      byte number;
      foreach (int numBase in bases)
      {
         Console.WriteLine("Base {0}:", numBase);
         foreach (string value in values)
         {
            try {
               number = Convert.ToByte(value, numBase);
               Console.WriteLine("   Converted '{0}' to {1}.", value, number);
            }
            catch (FormatException) {
               Console.WriteLine("   '{0}' is not in the correct format for a base {1} byte value.",
                                 value, numBase);
            }
            catch (OverflowException) {
               Console.WriteLine("   '{0}' is outside the range of the Byte type.", value);
            }
            catch (ArgumentException) {
               Console.WriteLine("   '{0}' is invalid in base {1}.", value, numBase);
            }
         }
      }
   }
}
// The example displays the following output:
//    Base 2:
//       '-1' is invalid in base 2.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 2 conversion.
//       '0F' is not in the correct format for a base 2 conversion.
//       Converted '11' to 3.
//       '12' is not in the correct format for a base 2 conversion.
//       '30' is not in the correct format for a base 2 conversion.
//       Converted '101' to 5.
//       '255' is not in the correct format for a base 2 conversion.
//       'FF' is not in the correct format for a base 2 conversion.
//       Converted '10000000' to 128.
//       '80' is not in the correct format for a base 2 conversion.
//    Base 8:
//       '-1' is invalid in base 8.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 8 conversion.
//       '0F' is not in the correct format for a base 8 conversion.
//       Converted '11' to 9.
//       Converted '12' to 10.
//       Converted '30' to 24.
//       Converted '101' to 65.
//       Converted '255' to 173.
//       'FF' is not in the correct format for a base 8 conversion.
//       '10000000' is outside the range of the Byte type.
//       '80' is not in the correct format for a base 8 conversion.
//    Base 10:
//       '-1' is outside the range of the Byte type.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       '0F' is not in the correct format for a base 10 conversion.
//       Converted '11' to 11.
//       Converted '12' to 12.
//       Converted '30' to 30.
//       Converted '101' to 101.
//       Converted '255' to 255.
//       'FF' is not in the correct format for a base 10 conversion.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 80.
//    Base 16:
//       '-1' is invalid in base 16.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       Converted '0F' to 15.
//       Converted '11' to 17.
//       Converted '12' to 18.
//       Converted '30' to 48.
//       '101' is outside the range of the Byte type.
//       '255' is outside the range of the Byte type.
//       Converted 'FF' to 255.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 128.

open System

let bases = [ 2; 8; 10; 16 ]
let values = 
    [| "-1"; "1"; "08"; "0F"; "11"; "12"; "30"
       "101"; "255"; "FF"; "10000000"; "80" |]

for numBase in bases do
    printfn $"Base {numBase}:"
    for value in values do
        try
            let number = Convert.ToByte(value, numBase)
            printfn $"   Converted '{value}' to {number}."
        with
        | :? FormatException ->
            printfn $"   '{value}' is not in the correct format for a base {numBase} byte value."
        | :? OverflowException ->
            printfn $"   '{value}' is outside the range of the Byte type."
        | :? ArgumentException ->
            printfn $"   '{value}' is invalid in base {numBase}."

// The example displays the following output:
//    Base 2:
//       '-1' is invalid in base 2.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 2 conversion.
//       '0F' is not in the correct format for a base 2 conversion.
//       Converted '11' to 3.
//       '12' is not in the correct format for a base 2 conversion.
//       '30' is not in the correct format for a base 2 conversion.
//       Converted '101' to 5.
//       '255' is not in the correct format for a base 2 conversion.
//       'FF' is not in the correct format for a base 2 conversion.
//       Converted '10000000' to 128.
//       '80' is not in the correct format for a base 2 conversion.
//    Base 8:
//       '-1' is invalid in base 8.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 8 conversion.
//       '0F' is not in the correct format for a base 8 conversion.
//       Converted '11' to 9.
//       Converted '12' to 10.
//       Converted '30' to 24.
//       Converted '101' to 65.
//       Converted '255' to 173.
//       'FF' is not in the correct format for a base 8 conversion.
//       '10000000' is outside the range of the Byte type.
//       '80' is not in the correct format for a base 8 conversion.
//    Base 10:
//       '-1' is outside the range of the Byte type.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       '0F' is not in the correct format for a base 10 conversion.
//       Converted '11' to 11.
//       Converted '12' to 12.
//       Converted '30' to 30.
//       Converted '101' to 101.
//       Converted '255' to 255.
//       'FF' is not in the correct format for a base 10 conversion.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 80.
//    Base 16:
//       '-1' is invalid in base 16.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       Converted '0F' to 15.
//       Converted '11' to 17.
//       Converted '12' to 18.
//       Converted '30' to 48.
//       '101' is outside the range of the Byte type.
//       '255' is outside the range of the Byte type.
//       Converted 'FF' to 255.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 128.

Module Example
   Public Sub Main()
      Dim bases() As Integer = { 2, 8, 10, 16 }
      Dim values() As String = { "-1", "1", "08", "0F", "11" , "12", "30", _                
                                  "101", "255", "FF", "10000000", "80" }
      Dim number As Byte
      For Each base As Integer In bases
         Console.WriteLine("Base {0}:", base)
         For Each value As String In values
            Try
               number = Convert.ToByte(value, base)
               Console.WriteLine("   Converted '{0}' to {1}.", value, number)
            Catch e As FormatException
               Console.WriteLine("   '{0}' is not in the correct format for a base {1} conversion.", _
                                 value, base)
            Catch e As OverflowException
               Console.WriteLine("   '{0}' is outside the range of the Byte type.", value)
            Catch e As ArgumentException
               Console.WriteLine("   '{0}' is invalid in base {1}.", value, base)
            End Try   
         Next                                 
      Next 
   End Sub
End Module
' The example displays the following output:
'    Base 2:
'       '-1' is invalid in base 2.
'       Converted '1' to 1.
'       '08' is not in the correct format for a base 2 conversion.
'       '0F' is not in the correct format for a base 2 conversion.
'       Converted '11' to 3.
'       '12' is not in the correct format for a base 2 conversion.
'       '30' is not in the correct format for a base 2 conversion.
'       Converted '101' to 5.
'       '255' is not in the correct format for a base 2 conversion.
'       'FF' is not in the correct format for a base 2 conversion.
'       Converted '10000000' to 128.
'       '80' is not in the correct format for a base 2 conversion.
'    Base 8:
'       '-1' is invalid in base 8.
'       Converted '1' to 1.
'       '08' is not in the correct format for a base 8 conversion.
'       '0F' is not in the correct format for a base 8 conversion.
'       Converted '11' to 9.
'       Converted '12' to 10.
'       Converted '30' to 24.
'       Converted '101' to 65.
'       Converted '255' to 173.
'       'FF' is not in the correct format for a base 8 conversion.
'       '10000000' is outside the range of the Byte type.
'       '80' is not in the correct format for a base 8 conversion.
'    Base 10:
'       '-1' is outside the range of the Byte type.
'       Converted '1' to 1.
'       Converted '08' to 8.
'       '0F' is not in the correct format for a base 10 conversion.
'       Converted '11' to 11.
'       Converted '12' to 12.
'       Converted '30' to 30.
'       Converted '101' to 101.
'       Converted '255' to 255.
'       'FF' is not in the correct format for a base 10 conversion.
'       '10000000' is outside the range of the Byte type.
'       Converted '80' to 80.
'    Base 16:
'       '-1' is invalid in base 16.
'       Converted '1' to 1.
'       Converted '08' to 8.
'       Converted '0F' to 15.
'       Converted '11' to 17.
'       Converted '12' to 18.
'       Converted '30' to 48.
'       '101' is outside the range of the Byte type.
'       '255' is outside the range of the Byte type.
'       Converted 'FF' to 255.
'       '10000000' is outside the range of the Byte type.
'       Converted '80' to 128.

Opmerkingen

Als fromBase dit 16 is, kunt u het nummer vooraf laten gaan dat is opgegeven door de value parameter met '0x' of '0X'.

Omdat het Byte gegevenstype alleen niet-ondertekende waarden ondersteunt, ToByte(String, Int32) wordt ervan uitgegaan dat deze value wordt uitgedrukt met behulp van niet-ondertekende binaire weergave. Met andere woorden, alle acht bits worden gebruikt om de numerieke waarde weer te geven en een tekenbit is afwezig. Als gevolg hiervan is het mogelijk om code te schrijven waarin een ondertekende bytewaarde die buiten het bereik van het Byte gegevenstype valt, wordt geconverteerd naar een Byte waarde zonder de methode die een uitzondering genereert. Het volgende voorbeeld wordt geconverteerd MinValue naar de hexadecimale tekenreeksweergave en roept vervolgens de ToByte(String, Int32) methode aan. In plaats van een uitzondering te genereren, wordt in de methode het bericht '0x80 wordt geconverteerd naar 128'.

// Create a hexadecimal value out of range of the Byte type.
string value = SByte.MinValue.ToString("X");
// Convert it back to a number.
try
{
   byte number = Convert.ToByte(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a byte.", value);
}

// Create a hexadecimal value out of range of the Byte type.
let value = SByte.MinValue.ToString "X"
// Convert it back to a number.
try
    let number = Convert.ToByte(value, 16)
    printfn $"0x{value} converts to {number}."
with :? OverflowException ->
    printfn $"Unable to convert '0x{value}' to a byte."

' Create a hexadecimal value out of range of the Byte type.
Dim value As String = SByte.MinValue.ToString("X")
' Convert it back to a number.
Try
   Dim number As Byte = Convert.ToByte(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a byte.", value)
End Try

Bij het uitvoeren van binaire bewerkingen of numerieke conversies is het altijd de verantwoordelijkheid van de ontwikkelaar om te controleren of een methode of operator de juiste numerieke weergave gebruikt om een bepaalde waarde te interpreteren. In het volgende voorbeeld ziet u één techniek om ervoor te zorgen dat de methode niet ongepast gebruik maakt van niet-ondertekende binaire weergave wanneer een hexadecimale tekenreeksweergave wordt geconverteerd naar een Byte waarde. In het voorbeeld wordt bepaald of een waarde een ondertekend of niet-ondertekend geheel getal vertegenwoordigt terwijl deze waarde wordt geconverteerd naar de tekenreeksweergave. Wanneer in het voorbeeld de waarde wordt geconverteerd naar een Byte waarde, wordt gecontroleerd of de oorspronkelijke waarde een ondertekend geheel getal is. Zo ja, en als de bit met hoge volgorde is ingesteld (wat aangeeft dat de waarde negatief is en dat er twee's complement wordt gebruikt in plaats van niet-ondertekende binaire weergave), genereert de methode een uitzondering.

// Create a negative hexadecimal value out of range of the Byte type.
sbyte sourceNumber = SByte.MinValue;
bool isSigned = Math.Sign((sbyte)sourceNumber.GetType().GetField("MinValue").GetValue(null)) == -1;
string value = sourceNumber.ToString("X");
byte targetNumber;
try
{
   targetNumber = Convert.ToByte(value, 16);
   if (isSigned && ((targetNumber & 0x80) != 0))
      throw new OverflowException();
   else
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to an unsigned byte.", value);
}
// Displays the following to the console:
//    Unable to convert '0x80' to an unsigned byte.

// Create a negative hexadecimal value out of range of the Byte type.
let sourceNumber = SByte.MinValue
let isSigned = sign (sourceNumber.GetType().GetField("MinValue").GetValue null :?> int8) = -1
let value = sourceNumber.ToString "X"
try
    let targetNumber = Convert.ToByte(value, 16)
    if isSigned && targetNumber &&& 0x80uy <> 0uy then
        raise (OverflowException())
    else
        printfn $"0x{value} converts to {targetNumber}."
with :? OverflowException ->
    printfn $"Unable to convert '0x{value}' to an unsigned byte."
// Displays the following to the console:
//    Unable to convert '0x80' to an unsigned byte.

' Create a negative hexadecimal value out of range of the Byte type.
Dim sourceNumber As SByte = SByte.MinValue
Dim isSigned As Boolean = Math.Sign(sourceNumber.MinValue) = -1
Dim value As String = sourceNumber.ToString("X")
Dim targetNumber As Byte
Try
   targetNumber = Convert.ToByte(value, 16)
   If isSigned And ((targetNumber And &H80) <> 0) Then
      Throw New OverflowException()
   Else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber)
   End If    
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to an unsigned byte.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0x80' to an unsigned byte.

Bron:

Convert.cs

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Convert.cs

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Convert.cs

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Convert.cs

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Convert.cs

public:
 static System::Byte ToByte(System::Object ^ value, IFormatProvider ^ provider);

public static byte ToByte(object value, IFormatProvider provider);

public static byte ToByte(object? value, IFormatProvider? provider);

static member ToByte : obj * IFormatProvider -> byte

Public Shared Function ToByte (value As Object, provider As IFormatProvider) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value, of nul als value dat is null.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een ByteString klasse gedefinieerd waarmee de IConvertible interface wordt geïmplementeerd. In de klasse wordt de tekenreeksweergave van een bytewaarde samen met een tekenveld opgeslagen, zodat deze zowel ondertekende als niet-ondertekende bytewaarden kan vertegenwoordigen.

using System;
using System.Globalization;

public enum SignBit { Negative=-1, Zero=0, Positive=1 };

public struct ByteString : IConvertible
{
   private SignBit signBit;
   private string byteString;

   public SignBit Sign
   {
      set { signBit = value; }
      get { return signBit; }
   }

   public string Value
   {
      set {
         if (value.Trim().Length > 2)
            throw new ArgumentException("The string representation of a byte cannot have more than two characters.");
         else
            byteString = value;
      }
      get { return byteString; }
   }

   // IConvertible implementations.
   public TypeCode GetTypeCode() {
      return TypeCode.Object;
   }

   public bool ToBoolean(IFormatProvider provider)
   {
      if (signBit == SignBit.Zero)
         return false;
      else
         return true;
   }

   public byte ToByte(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16)));
      else
         return Byte.Parse(byteString, NumberStyles.HexNumber);
   }

   public char ToChar(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative) {
         throw new OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)));
      }
      else {
         byte byteValue = Byte.Parse(this.byteString, NumberStyles.HexNumber);
         return Convert.ToChar(byteValue);
      }
   }

   public DateTime ToDateTime(IFormatProvider provider)
   {
      throw new InvalidCastException("ByteString to DateTime conversion is not supported.");
   }

   public decimal ToDecimal(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
      {
         sbyte byteValue = SByte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
      else
      {
         byte byteValue = Byte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
   }

   public double ToDouble(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public short ToInt16(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public int ToInt32(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public long ToInt64(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public sbyte ToSByte(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         try {
            return Convert.ToSByte(Byte.Parse(byteString, NumberStyles.HexNumber));
         }
         catch (OverflowException e) {
            throw new OverflowException(String.Format("{0} is outside the range of the SByte type.",
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)), e);
         }
      else
         return SByte.Parse(byteString, NumberStyles.HexNumber);
   }

   public float ToSingle(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public string ToString(IFormatProvider provider)
   {
      return "0x" + this.byteString;
   }

   public object ToType(Type conversionType, IFormatProvider provider)
   {
      switch (Type.GetTypeCode(conversionType))
      {
         case TypeCode.Boolean:
            return this.ToBoolean(null);
         case TypeCode.Byte:
            return this.ToByte(null);
         case TypeCode.Char:
            return this.ToChar(null);
         case TypeCode.DateTime:
            return this.ToDateTime(null);
         case TypeCode.Decimal:
            return this.ToDecimal(null);
         case TypeCode.Double:
            return this.ToDouble(null);
         case TypeCode.Int16:
            return this.ToInt16(null);
         case TypeCode.Int32:
            return this.ToInt32(null);
         case TypeCode.Int64:
            return this.ToInt64(null);
         case TypeCode.Object:
            if (typeof(ByteString).Equals(conversionType))
               return this;
            else
               throw new InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name));
         case TypeCode.SByte:
            return this.ToSByte(null);
         case TypeCode.Single:
            return this.ToSingle(null);
         case TypeCode.String:
            return this.ToString(null);
         case TypeCode.UInt16:
            return this.ToUInt16(null);
         case TypeCode.UInt32:
            return this.ToUInt32(null);
         case TypeCode.UInt64:
            return this.ToUInt64(null);
         default:
            throw new InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name));
      }
   }

   public UInt16 ToUInt16(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt16 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public UInt32 ToUInt32(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt32 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public UInt64 ToUInt64(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt64 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
}

open System
open System.Globalization

type SignBit =
   | Negative = -1
   | Zero = 0
   | Positive = 1

[<Struct>]
type ByteString =
    val mutable private value: string
    
    val mutable Sign : SignBit
    member this.Value
        with get () = this.value
        and set (value: string) =
            if value.Trim().Length > 2 then
                invalidArg "value" "The string representation of a byte cannot have more than two characters"
            else
                this.value <- value 

    // IConvertible implementations.
    interface IConvertible with
        member _.GetTypeCode() =
            TypeCode.Object

        member this.ToBoolean(provider: IFormatProvider) =
            this.Sign <> SignBit.Zero

        member this.ToByte(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                raise (OverflowException $"{Convert.ToSByte(this.value, 16)} is out of range of the Byte type.")
            else
                Byte.Parse(this.value, NumberStyles.HexNumber)

        member this.ToChar(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                raise (OverflowException $"{Convert.ToSByte(this.value, 16)} is out of range of the Char type.")
            else
                let byteValue = Byte.Parse(this.value, NumberStyles.HexNumber)
                Convert.ToChar byteValue

        member _.ToDateTime(provider: IFormatProvider) =
            raise (InvalidCastException "ByteString to DateTime conversion is not supported.")

        member this.ToDecimal(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                let byteValue = SByte.Parse(this.Value, NumberStyles.HexNumber)
                Convert.ToDecimal byteValue
            else
                let byteValue = Byte.Parse(this.Value, NumberStyles.HexNumber)
                Convert.ToDecimal byteValue

        member this.ToDouble(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                Convert.ToDouble(SByte.Parse(this.value, NumberStyles.HexNumber))
            else
                Convert.ToDouble(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToInt16(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                Convert.ToInt16(SByte.Parse(this.value, NumberStyles.HexNumber))
            else
                Convert.ToInt16(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToInt32(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                Convert.ToInt32(SByte.Parse(this.value, NumberStyles.HexNumber))
            else
                Convert.ToInt32(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToInt64(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                Convert.ToInt64(SByte.Parse(this.value, NumberStyles.HexNumber))
            else
                Convert.ToInt64(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToSByte(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                try
                    Convert.ToSByte(Byte.Parse(this.value, NumberStyles.HexNumber))
                with :? OverflowException as e ->
                    raise (OverflowException($"{Byte.Parse(this.value, NumberStyles.HexNumber)} is outside the range of the SByte type.", e))
            else
                SByte.Parse(this.value, NumberStyles.HexNumber)

        member this.ToSingle(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                Convert.ToSingle(SByte.Parse(this.value, NumberStyles.HexNumber))
            else
                Convert.ToSingle(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToString(provider: IFormatProvider) =
            "0x" + this.value

        member this.ToType(conversionType: Type, provider: IFormatProvider): obj =
            let this = this :> IConvertible
            match Type.GetTypeCode conversionType with
            | TypeCode.Boolean ->
                this.ToBoolean null
            | TypeCode.Byte ->
                this.ToByte null
            | TypeCode.Char ->
                this.ToChar null
            | TypeCode.DateTime ->
                this.ToDateTime null
            | TypeCode.Decimal ->
                this.ToDecimal null
            | TypeCode.Double ->
                this.ToDouble null
            | TypeCode.Int16 ->
                this.ToInt16 null
            | TypeCode.Int32 ->
                this.ToInt32 null
            | TypeCode.Int64 ->
                this.ToInt64 null
            | TypeCode.Object ->
                if typeof<ByteString>.Equals conversionType then
                    this
                else
                    raise (InvalidCastException $"Conversion to a {conversionType.Name} is not supported.")
            | TypeCode.SByte ->
                this.ToSByte null
            | TypeCode.Single ->
                this.ToSingle null
            | TypeCode.String ->
                this.ToString null
            | TypeCode.UInt16 ->
                this.ToUInt16 null
            | TypeCode.UInt32 ->
                this.ToUInt32 null
            | TypeCode.UInt64 ->
                this.ToUInt64 null
            | _ ->
                raise (InvalidCastException $"Conversion to {conversionType.Name} is not supported.")

        member this.ToUInt16(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                raise (OverflowException $"{SByte.Parse(this.value, NumberStyles.HexNumber)} is outside the range of the UInt16 type.")
            else
                Convert.ToUInt16(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToUInt32(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                raise (OverflowException $"{SByte.Parse(this.value, NumberStyles.HexNumber)} is outside the range of the UInt32 type.")
            else
                Convert.ToUInt32(Byte.Parse(this.value, NumberStyles.HexNumber))

        member this.ToUInt64(provider: IFormatProvider) =
            if this.Sign = SignBit.Negative then
                raise (OverflowException $"{SByte.Parse(this.value, NumberStyles.HexNumber)} is outside the range of the UInt64 type.")
            else
                Convert.ToUInt64(Byte.Parse(this.value, NumberStyles.HexNumber))

Imports System.Globalization

Public Enum SignBit As Integer
   Positive = 1
   Zero = 0
   Negative = -1
End Enum

Public Structure ByteString : Implements IConvertible
   Private signBit As SignBit
   Private byteString As String
   
   Public Property Sign As SignBit
      Set
         signBit = value
      End Set
      Get
         Return signBit
      End Get
   End Property
   
   Public Property Value As String
      Set
         If value.Trim().Length > 2 Then
            Throw New ArgumentException("The string representation of a byte cannot have more than two characters.")
         Else
            byteString = value
         End If   
      End Set
      Get
         Return byteString
      End Get
   End Property
   
   ' IConvertible implementations.
   Public Function GetTypeCode() As TypeCode _
                   Implements IConvertible.GetTypeCode
      Return TypeCode.Object
   End Function
   
   Public Function ToBoolean(provider As IFormatProvider) As Boolean _
                   Implements IConvertible.ToBoolean
      If signBit = SignBit.Zero Then
         Return False
      Else
         Return True
      End If
   End Function 
   
   Public Function ToByte(provider As IFormatProvider) As Byte _
                   Implements IConvertible.ToByte
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16))) 
      Else
         Return Byte.Parse(byteString, NumberStyles.HexNumber)
      End If       
   End Function
   
   Public Function ToChar(provider As IFormatProvider) As Char _
                   Implements IConvertible.ToChar
      If signBit = signBit.Negative Then 
         Throw New OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)))
      Else
         Dim byteValue As Byte = Byte.Parse(Me.byteString, NumberStyles.HexNumber)
         Return Convert.ToChar(byteValue)
      End If                
   End Function 
   
   Public Function ToDateTime(provider As IFormatProvider) As Date _
                   Implements IConvertible.ToDateTime
      Throw New InvalidCastException("ByteString to DateTime conversion is not supported.")
   End Function
   
   Public Function ToDecimal(provider As IFormatProvider) As Decimal _
                   Implements IConvertible.ToDecimal
      If signBit = signBit.Negative Then
         Dim byteValue As SByte = SByte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      Else
         Dim byteValue As Byte = Byte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      End If
   End Function
   
   Public Function ToDouble(provider As IFormatProvider) As Double _
                   Implements IConvertible.ToDouble
      If signBit = signBit.Negative Then
         Return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function   
   
   Public Function ToInt16(provider As IFormatProvider) As Int16 _
                   Implements IConvertible.ToInt16
      If signBit = signBit.Negative Then
         Return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt32(provider As IFormatProvider) As Int32 _
                   Implements IConvertible.ToInt32
      If signBit = signBit.Negative Then
         Return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt64(provider As IFormatProvider) As Int64 _
                   Implements IConvertible.ToInt64
      If signBit = signBit.Negative Then
         Return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToSByte(provider As IFormatProvider) As SByte _
                   Implements IConvertible.ToSByte
      If signBit = SignBit.Positive Then
         Try
            Return Convert.ToSByte(Byte.Parse(byteString, NumberStyles.HexNumber))
         Catch e As OverflowException
            Throw New OverflowException(String.Format("{0} is outside the range of the SByte type.", _
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)), e)   
         End Try
      Else
         Return SByte.Parse(byteString, NumberStyles.HexNumber)
      End If
   End Function

   Public Function ToSingle(provider As IFormatProvider) As Single _
                   Implements IConvertible.ToSingle
      If signBit = signBit.Negative Then
         Return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Overloads Function ToString(provider As IFormatProvider) As String _
                   Implements IConvertible.ToString
      Return Me.byteString
   End Function
   
   Public Function ToType(conversionType As Type, provider As IFormatProvider) As Object _
                   Implements IConvertible.ToType
      Select Case Type.GetTypeCode(conversionType)
         Case TypeCode.Boolean 
            Return Me.ToBoolean(Nothing)
         Case TypeCode.Byte
            Return Me.ToByte(Nothing)
         Case TypeCode.Char
            Return Me.ToChar(Nothing)
         Case TypeCode.DateTime
            Return Me.ToDateTime(Nothing)
         Case TypeCode.Decimal
            Return Me.ToDecimal(Nothing)
         Case TypeCode.Double
            Return Me.ToDouble(Nothing)
         Case TypeCode.Int16
            Return Me.ToInt16(Nothing)
         Case TypeCode.Int32
            Return Me.ToInt32(Nothing)
         Case TypeCode.Int64
            Return Me.ToInt64(Nothing)
         Case TypeCode.Object
            If GetType(ByteString).Equals(conversionType) Then
               Return Me
            Else
               Throw New InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name))
            End If 
         Case TypeCode.SByte
            Return Me.ToSByte(Nothing)
         Case TypeCode.Single
            Return Me.ToSingle(Nothing)
         Case TypeCode.String
            Return Me.ToString(Nothing)
         Case TypeCode.UInt16
            Return Me.ToUInt16(Nothing)
         Case TypeCode.UInt32
            Return Me.ToUInt32(Nothing)
         Case TypeCode.UInt64
            Return Me.ToUInt64(Nothing)   
         Case Else
            Throw New InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name))   
            
      End Select
   End Function
   
   Public Function ToUInt16(provider As IFormatProvider) As UInt16 _
                   Implements IConvertible.ToUInt16
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt16 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Function ToUInt32(provider As IFormatProvider) As UInt32 _
                   Implements IConvertible.ToUInt32
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt32 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToUInt64(provider As IFormatProvider) As UInt64 _
                   Implements IConvertible.ToUInt64
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt64 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
End Structure

In het volgende voorbeeld worden verschillende ByteString objecten geïnstitueerd en wordt de ToByte(Object, IFormatProvider) methode aangeroepen om ze te converteren naar bytewaarden. Het illustreert dat de ToByte(Object, IFormatProvider) methode een aanroep verpakt naar de IConvertible.ToByte methode van het object dat moet worden geconverteerd.

public class Class1
{
   public static void Main()
   {
      byte positiveByte = 216;
      sbyte negativeByte = -101;

      ByteString positiveString = new ByteString();
      positiveString.Sign = (SignBit) Math.Sign(positiveByte);
      positiveString.Value = positiveByte.ToString("X2");

      ByteString negativeString = new ByteString();
      negativeString.Sign = (SignBit) Math.Sign(negativeByte);
      negativeString.Value = negativeByte.ToString("X2");

      try {
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToByte(positiveString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value);
      }

      try {
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToByte(negativeString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value);
      }
   }
}
// The example displays the following output:
//       'D8' converts to 216.
//       0x9B is outside the range of the Byte type.

let positiveByte = 216uy
let negativeByte = -101y

let mutable positiveString = ByteString()
positiveString.Sign <- Math.Sign positiveByte |> enum
positiveString.Value <- positiveByte.ToString "X2"

let mutable negativeString = ByteString()
negativeString.Sign <- Math.Sign negativeByte |> enum
negativeString.Value <- negativeByte.ToString "X2"

try
    printfn $"'{positiveString.Value}' converts to {Convert.ToByte positiveString}."
with :? OverflowException ->
    printfn $"0x{positiveString.Value} is outside the range of the Byte type."

try
    printfn $"'{negativeString.Value}' converts to {Convert.ToByte negativeString}."
with :? OverflowException ->
    printfn $"0x{negativeString.Value} is outside the range of the Byte type."

// The example displays the following output:
//       'D8' converts to 216.
//       0x9B is outside the range of the Byte type.

Module modMain
   Public Sub Main()
      Dim positiveByte As Byte = 216
      Dim negativeByte As SByte = -101
      
      
      Dim positiveString As New ByteString()
      positiveString.Sign = CType(Math.Sign(positiveByte), SignBit)
      positiveString.Value = positiveByte.ToString("X2")
      
      Dim negativeString As New ByteString()
      negativeString.Sign = CType(Math.Sign(negativeByte), SignBit)
      negativeString.Value = negativeByte.ToString("X2")
      
      Try
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToByte(positiveString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value)
      End Try

      Try
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToByte(negativeString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value)
      End Try   
   End Sub
End Module
' The example dosplays the following output:
'       'D8' converts to 216.
'       0x9B is outside the range of the Byte type.

Opmerkingen

provider stelt de gebruiker in staat om cultuurspecifieke conversiegegevens op te geven over de inhoud van value. De basistypen negeren provider; de parameter kan echter worden gebruikt als value een door de gebruiker gedefinieerd type is dat de IConvertible interface implementeert.

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

public:
 static System::Byte ToByte(System::String ^ value, IFormatProvider ^ provider);

public static byte ToByte(string value, IFormatProvider provider);

public static byte ToByte(string? value, IFormatProvider? provider);

static member ToByte : string * IFormatProvider -> byte

Public Shared Function ToByte (value As String, provider As IFormatProvider) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value, of nul als value dat is null.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een aangepast NumberFormatInfo object gemaakt dat het positieve teken definieert als 'pos' en het negatieve teken als 'neg', dat wordt gebruikt in aanroepen naar de ToByte(String, IFormatProvider) methode. Vervolgens wordt de ToByte(String, IFormatProvider) methode herhaaldelijk aangeroepen om elk element in een tekenreeksmatrix te converteren naar een Byte waarde.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      // Create a NumberFormatInfo object and set several of its
      // properties that apply to unsigned bytes.
      NumberFormatInfo provider = new NumberFormatInfo();

      // These properties affect the conversion.
      provider.PositiveSign = "pos ";
      provider.NegativeSign = "neg ";

      // This property does not affect the conversion.
      // The input string cannot have a decimal separator.
      provider.NumberDecimalSeparator = ".";

      // Define an array of numeric strings.
      string[] numericStrings = { "234", "+234", "pos 234", "234.", "255",
                                  "256", "-1" };

      foreach (string numericString in numericStrings)
      {
         Console.Write("'{0,-8}' ->   ", numericString);
         try {
            byte number = Convert.ToByte(numericString, provider);
            Console.WriteLine(number);
         }
         catch (FormatException) {
            Console.WriteLine("Incorrect Format");
         }
         catch (OverflowException) {
            Console.WriteLine("Overflows a Byte");
         }
      }
   }
}
// The example displays the following output:
//       '234     ' ->   234
//       '+234    ' ->   Incorrect Format
//       'pos 234 ' ->   234
//       '234.    ' ->   Incorrect Format
//       '255     ' ->   255
//       '256     ' ->   Overflows a Byte
//       '-1      ' ->   Incorrect Format

open System
open System.Globalization

// Create a NumberFormatInfo object and set several of its
// properties that apply to unsigned bytes.
let provider = NumberFormatInfo()

// These properties affect the conversion.
provider.PositiveSign <- "pos "
provider.NegativeSign <- "neg "

// This property does not affect the conversion.
// The input string cannot have a decimal separator.
provider.NumberDecimalSeparator <- "."

// Define an array of numeric strings.
let numericStrings = 
    [| "234"; "+234"; "pos 234"
       "234."; "255"; "256"; "-1" |]

for numericString in numericStrings do
    printf $"'{numericString,-8}' ->   "
    try
        let number = Convert.ToByte(numericString, provider)
        printfn $"{number}"
    with
    | :? FormatException ->
        printfn "Incorrect Format"
    | :? OverflowException ->
        printfn "Overflows a Byte"

// The example displays the following output:
//       '234     ' ->   234
//       '+234    ' ->   Incorrect Format
//       'pos 234 ' ->   234
//       '234.    ' ->   Incorrect Format
//       '255     ' ->   255
//       '256     ' ->   Overflows a Byte
//       '-1      ' ->   Incorrect Format

Imports System.Globalization

Module Example
   Public Sub Main()
      ' Create a NumberFormatInfo object and set several of its
      ' properties that apply to unsigned bytes.
      Dim provider As New NumberFormatInfo()
      With provider 
         ' These properties affect the conversion.
         .PositiveSign = "pos "
         .NegativeSign = "neg "

         ' This property does not affect the conversion.
         ' The input string cannot have a decimal separator.
         .NumberDecimalSeparator = "."
      End With
      
      ' Define an array of numeric strings.
      Dim numericStrings() As String = { "234", "+234", "pos 234", "234.", _
                                         "255", "256", "-1" }

      For Each numericString As String In numericStrings
         Console.Write("'{0,-8}' ->   ", numericString)
         Try
            Dim number As Byte = Convert.ToByte(numericString, provider)
            Console.WriteLine(number)
         Catch ex As FormatException
            Console.WriteLine("Incorrect Format")                          
         Catch ex As OverflowException
            Console.WriteLine("Overflows a Byte")
         End Try   
      Next
   End Sub   
End Module 
' The example displays the following output:
'       '234     ' ->   234
'       '+234    ' ->   Incorrect Format
'       'pos 234 ' ->   234
'       '234.    ' ->   Incorrect Format
'       '255     ' ->   255
'       '256     ' ->   Overflows a Byte
'       '-1      ' ->   Incorrect Format

Opmerkingen

provider is een IFormatProvider exemplaar dat een NumberFormatInfo object verkrijgt. Het NumberFormatInfo object biedt cultuurspecifieke informatie over de indeling van value. Als provider dat het is null, wordt het NumberFormatInfo object voor de huidige cultuur gebruikt.

Als u liever geen uitzondering afhandelt als de conversie mislukt, kunt u in plaats daarvan de Byte.TryParse methode aanroepen. Het retourneert een Boolean waarde die aangeeft of de conversie is geslaagd of mislukt.

Zie ook

• Parse(String)

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public:
 static System::Byte ToByte(float value);

public static byte ToByte(float value);

static member ToByte : single -> byte

Public Shared Function ToByte (value As Single) As Byte

Parameters

Retouren

value, afgerond op het dichtstbijzijnde 8-bits niet-ondertekende gehele getal. Als value het halverwege twee gehele getallen is, wordt het even getal geretourneerd. Dat wil gezegd: 4,5 wordt geconverteerd naar 4 en 5,5 wordt geconverteerd naar 6.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een Single waarde geconverteerd naar een Byte.

public void ConvertByteSingle(byte byteVal) {
    float floatVal;

    // Byte to float conversion will not overflow.
    floatVal = System.Convert.ToSingle(byteVal);
    System.Console.WriteLine("The byte as a float is {0}.",
        floatVal);

    // Float to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(floatVal);
        System.Console.WriteLine("The float as a byte is {0}.",
            byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "The float value is too large for a byte.");
    }
}

let convertByteSingle (byteVal: byte) =
    // Byte to float conversion will not overflow.
    let floatVal = Convert.ToSingle byteVal
    printfn $"The byte as a float is {floatVal}."

    // Float to byte conversion can overflow.
    try
        let byteVal = Convert.ToByte floatVal
        printfn $"The float as a byte is {byteVal}."
    with :? OverflowException ->
        printfn "The float value is too large for a byte."

Public Sub ConvertByteSingle(ByVal byteVal As Byte)
    Dim singleVal As Single

    ' Byte to float conversion will not overflow.
    singleVal = System.Convert.ToSingle(byteVal)
    System.Console.WriteLine("The byte as a single is {0}.", _
                              singleVal)

    ' Single to byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(singleVal)
        System.Console.WriteLine("The single as a byte is {0}.", _
                                  byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in single-to-byte conversion.")
    End Try
End Sub

Zie ook

• Round

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public:
 static System::Byte ToByte(System::UInt64 value);

[System.CLSCompliant(false)]
public static byte ToByte(ulong value);

[<System.CLSCompliant(false)>]
static member ToByte : uint64 -> byte

Public Shared Function ToByte (value As ULong) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Kenmerken

CLSCompliantAttribute

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met niet-ondertekende lange gehele getallen geconverteerd naar Byte waarden.

ulong[] numbers= { UInt64.MinValue, 121, 340, UInt64.MaxValue };
byte result;
foreach (ulong number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt64 value 0 to the Byte value 0.
//       Converted the UInt64 value 121 to the Byte value 121.
//       The UInt64 value 340 is outside the range of the Byte type.
//       The UInt64 value 18446744073709551615 is outside the range of the Byte type.

let numbers= [| UInt64.MinValue; 121uL; 340uL; UInt64.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       Converted the UInt64 value 0 to the Byte value 0.
//       Converted the UInt64 value 121 to the Byte value 121.
//       The UInt64 value 340 is outside the range of the Byte type.
//       The UInt64 value 18446744073709551615 is outside the range of the Byte type.

Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As Byte
For Each number As ULong In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt64 value 0 to the Byte value 0.
'       Converted the UInt64 value 121 to the Byte value 121.
'       The UInt64 value 340 is outside the range of the Byte type.
'       The UInt64 value 18446744073709551615 is outside the range of the Byte type.

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public:
 static System::Byte ToByte(System::SByte value);

[System.CLSCompliant(false)]
public static byte ToByte(sbyte value);

[<System.CLSCompliant(false)>]
static member ToByte : sbyte -> byte

Public Shared Function ToByte (value As SByte) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Kenmerken

CLSCompliantAttribute

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met SByte waarden geconverteerd naar Byte waarden.

sbyte[] numbers = { SByte.MinValue, -1, 0, 10, SByte.MaxValue };
byte result;
foreach (sbyte number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The SByte value -128 is outside the range of the Byte type.
//       The SByte value -1 is outside the range of the Byte type.
//       Converted the SByte value 0 to the Byte value 0.
//       Converted the SByte value 10 to the Byte value 10.
//       Converted the SByte value 127 to the Byte value 127.

let numbers = [| SByte.MinValue; -1y; 0y; 10y; SByte.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       The SByte value -128 is outside the range of the Byte type.
//       The SByte value -1 is outside the range of the Byte type.
//       Converted the SByte value 0 to the Byte value 0.
//       Converted the SByte value 10 to the Byte value 10.
//       Converted the SByte value 127 to the Byte value 127.

Dim numbers() As SByte = { SByte.MinValue, -1, 0, 10, SByte.MaxValue }
Dim result As Byte
For Each number As SByte In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The SByte value -128 is outside the range of the Byte type.
'       The SByte value -1 is outside the range of the Byte type.
'       Converted the SByte value 0 to the Byte value 0.
'       Converted the SByte value 10 to the Byte value 10.
'       Converted the SByte value 127 to the Byte value 127.

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public:
 static System::Byte ToByte(char value);

public static byte ToByte(char value);

static member ToByte : char -> byte

Public Shared Function ToByte (value As Char) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met Char waarden geconverteerd naar Byte waarden.

char[] chars = { 'a', 'z', '\x0007', '\x03FF' };
foreach (char ch in chars)
{
   try {
      byte result = Convert.ToByte(ch);
      Console.WriteLine("{0} is converted to {1}.", ch, result);
   }
   catch (OverflowException) {
      Console.WriteLine("Unable to convert u+{0} to a byte.",
                        Convert.ToInt16(ch).ToString("X4"));
   }
}
// The example displays the following output:
//       a is converted to 97.
//       z is converted to 122.
//        is converted to 7.
//       Unable to convert u+03FF to a byte.

let chars = [| 'a'; 'z'; '\u0007'; '\u03FF' |]
for ch in chars do
    try
        let result = Convert.ToByte ch
        printfn $"{ch} is converted to {result}."
    with :? OverflowException ->
        printfn $"Unable to convert u+{Convert.ToInt16 ch:X4} to a byte."
// The example displays the following output:
//       a is converted to 97.
//       z is converted to 122.
//        is converted to 7.
//       Unable to convert u+03FF to a byte.

Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(1023) }
For Each ch As Char in chars
   Try
      Dim result As Byte = Convert.ToByte(ch)
      Console.WriteLine("{0} is converted to {1}.", ch, result)
   Catch e As OverflowException
      Console.WriteLIne("Unable to convert u+{0} to a byte.", _
                        AscW(ch).ToString("X4"))
   End Try
Next   
' The example displays the following output:
'       a is converted to 97.
'       z is converted to 122.
'        is converted to 7.
'       Unable to convert u+03FF to a byte.

Opmerkingen

Deze methode retourneert een niet-ondertekende bytewaarde die de numerieke code vertegenwoordigt van het Char object dat eraan is doorgegeven. In .NET is een Char-object een 16-bits waarde. Dit betekent dat de methode geschikt is voor het retourneren van de numerieke codes van tekens in het ASCII-tekenbereik of in de Unicode C0-besturingselementen en het Basis-Latijns, en C1 Controls and Latin-1 Supplement bereiken, van U+0000 tot U+00FF.

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public:
 static System::Byte ToByte(long value);

public static byte ToByte(long value);

static member ToByte : int64 -> byte

Public Shared Function ToByte (value As Long) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met Int64 waarden geconverteerd naar Byte waarden.

long[] numbers = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue };
byte result;
foreach (long number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int64 value -9223372036854775808 is outside the range of the Byte type.
//       The Int64 value -1 is outside the range of the Byte type.
//       Converted the Int64 value 0 to the Byte value 0.
//       Converted the Int64 value 121 to the Byte value 121.
//       The Int64 value 340 is outside the range of the Byte type.
//       The Int64 value 9223372036854775807 is outside the range of the Byte type.

let numbers = [| Int64.MinValue; -1L; 0L; 121L; 34L; Int64.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       The Int64 value -9223372036854775808 is outside the range of the Byte type.
//       The Int64 value -1 is outside the range of the Byte type.
//       Converted the Int64 value 0 to the Byte value 0.
//       Converted the Int64 value 121 to the Byte value 121.
//       The Int64 value 340 is outside the range of the Byte type.
//       The Int64 value 9223372036854775807 is outside the range of the Byte type.

Dim numbers() As Long = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue }
Dim result As Byte
For Each number As Long In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int64 value -9223372036854775808 is outside the range of the Byte type.
'       The Int64 value -1 is outside the range of the Byte type.
'       Converted the Int64 value 0 to the Byte value 0.
'       Converted the Int64 value 121 to the Byte value 121.
'       The Int64 value 340 is outside the range of the Byte type.
'       The Int64 value 9223372036854775807 is outside the range of the Byte type.

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public:
 static System::Byte ToByte(System::Byte value);

public static byte ToByte(byte value);

static member ToByte : byte -> byte

Public Shared Function ToByte (value As Byte) As Byte

Parameters

Retouren

value wordt ongewijzigd geretourneerd.

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public:
 static System::Byte ToByte(DateTime value);

public static byte ToByte(DateTime value);

static member ToByte : DateTime -> byte

Public Shared Function ToByte (value As DateTime) As Byte

Parameters

Retouren

Deze conversie wordt niet ondersteund. Er wordt geen waarde geretourneerd.

Uitzonderingen

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public:
 static System::Byte ToByte(System::Decimal value);

public static byte ToByte(decimal value);

static member ToByte : decimal -> byte

Public Shared Function ToByte (value As Decimal) As Byte

Parameters

Retouren

value, afgerond op het dichtstbijzijnde 8-bits niet-ondertekende gehele getal. Als value het halverwege twee gehele getallen is, wordt het even getal geretourneerd. Dat wil gezegd: 4,5 wordt geconverteerd naar 4 en 5,5 wordt geconverteerd naar 6.

Uitzonderingen

Opmerkingen

In het volgende voorbeeld wordt een Byte waarde geconverteerd naar een Decimal en een Decimal waarde naar een Byte.

public void ConvertByteDecimal(byte byteVal) {
    decimal decimalVal;

    // Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal);
    System.Console.WriteLine("The byte as a decimal is {0}.",
        decimalVal);

    // Decimal to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(decimalVal);
        System.Console.WriteLine("The Decimal as a byte is {0}.",
            byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "The decimal value is too large for a byte.");
    }
}

let convertByteDecimal (byteVal: byte) =
    // Byte to decimal conversion will not overflow.
    let decimalVal = Convert.ToDecimal byteVal
    printfn $"The byte as a decimal is {decimalVal}."

    // Decimal to byte conversion can overflow.
    try
        let byteVal = Convert.ToByte decimalVal
        printfn $"The Decimal as a byte is {byteVal}."
    with :? OverflowException ->
        printfn "The decimal value is too large for a byte."

Public Sub ConvertByteDecimal(ByVal byteVal As Byte)
    Dim decimalVal As Decimal

    ' Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal)
    System.Console.WriteLine("The byte as a decimal is {0}.", _
                              decimalVal)

    ' Decimal to byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(decimalVal)
        System.Console.WriteLine("The Decimal as a byte is {0}.", _
                                  byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in decimal-to-byte conversion.")
    End Try
End Sub

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public:
 static System::Byte ToByte(bool value);

public static byte ToByte(bool value);

static member ToByte : bool -> byte

Public Shared Function ToByte (value As Boolean) As Byte

Parameters

Retouren

Het getal 1 als value dit is true; anders, 0.

Voorbeelden

In het volgende voorbeeld ziet u de conversie van Boolean waarden Byte .

bool falseFlag = false;
bool trueFlag = true;

Console.WriteLine("{0} converts to {1}.", falseFlag,
                  Convert.ToByte(falseFlag));
Console.WriteLine("{0} converts to {1}.", trueFlag,
                  Convert.ToByte(trueFlag));
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.

let falseFlag = false
let trueFlag = true

printfn $"{falseFlag} converts to {Convert.ToByte falseFlag}."
printfn $"{trueFlag} converts to {Convert.ToByte trueFlag}."
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.

Dim falseFlag As Boolean = False
Dim trueFlag As Boolean = True

Console.WriteLine("{0} converts to {1}.", falseFlag, _
                  Convert.ToByte(falseFlag))
Console.WriteLine("{0} converts to {1}.", trueFlag, _
                  Convert.ToByte(trueFlag))
' The example displays the following output:
'       False converts to 0.
'       True converts to 1.

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public:
 static System::Byte ToByte(short value);

public static byte ToByte(short value);

static member ToByte : int16 -> byte

Public Shared Function ToByte (value As Short) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met Int16 waarden geconverteerd naar Byte waarden.

short[] numbers = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue };
byte result;
foreach (short number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int16 value -32768 is outside the range of the Byte type.
//       The Int16 value -1 is outside the range of the Byte type.
//       Converted the Int16 value 0 to the Byte value 0.
//       Converted the Int16 value 121 to the Byte value 121.
//       The Int16 value 340 is outside the range of the Byte type.
//       The Int16 value 32767 is outside the range of the Byte type.

let numbers = [| Int16.MinValue; -1s; 0s; 121s; 340s; Int16.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       The Int16 value -32768 is outside the range of the Byte type.
//       The Int16 value -1 is outside the range of the Byte type.
//       Converted the Int16 value 0 to the Byte value 0.
//       Converted the Int16 value 121 to the Byte value 121.
//       The Int16 value 340 is outside the range of the Byte type.
//       The Int16 value 32767 is outside the range of the Byte type.

Dim numbers() As Short = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue }
Dim result As Byte
For Each number As Short In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int16 value -32768 is outside the range of the Byte type.
'       The Int16 value -1 is outside the range of the Byte type.
'       Converted the Int16 value 0 to the Byte value 0.
'       Converted the Int16 value 121 to the Byte value 121.
'       The Int16 value 340 is outside the range of the Byte type.
'       The Int16 value 32767 is outside the range of the Byte type.

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Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

public:
 static System::Byte ToByte(int value);

public static byte ToByte(int value);

static member ToByte : int -> byte

Public Shared Function ToByte (value As Integer) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een matrix met Int32 waarden geconverteerd naar Byte waarden.

int[] numbers = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue };
byte result;
foreach (int number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int32 value -2147483648 is outside the range of the Byte type.
//       The Int32 value -1 is outside the range of the Byte type.
//       Converted the Int32 value 0 to the Byte value 0.
//       Converted the Int32 value 121 to the Byte value 121.
//       The Int32 value 340 is outside the range of the Byte type.
//       The Int32 value 2147483647 is outside the range of the Byte type.

let numbers = [| Int32.MinValue; -1; 0; 121; 340; Int32.MaxValue |]
for number in numbers do
    try
        let result = Convert.ToByte number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Byte type."
// The example displays the following output:
//       The Int32 value -2147483648 is outside the range of the Byte type.
//       The Int32 value -1 is outside the range of the Byte type.
//       Converted the Int32 value 0 to the Byte value 0.
//       Converted the Int32 value 121 to the Byte value 121.
//       The Int32 value 340 is outside the range of the Byte type.
//       The Int32 value 2147483647 is outside the range of the Byte type.

Dim numbers() As Integer = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue }
Dim result As Byte
For Each number As Integer In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int32 value -2147483648 is outside the range of the Byte type.
'       The Int32 value -1 is outside the range of the Byte type.
'       Converted the Int32 value 0 to the Byte value 0.
'       Converted the Int32 value 121 to the Byte value 121.
'       The Int32 value 340 is outside the range of the Byte type.
'       The Int32 value 2147483647 is outside the range of the Byte type.

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

Bron:

Convert.cs

public:
 static System::Byte ToByte(double value);

public static byte ToByte(double value);

static member ToByte : double -> byte

Public Shared Function ToByte (value As Double) As Byte

Parameters

Retouren

value, afgerond op het dichtstbijzijnde 8-bits niet-ondertekende gehele getal. Als value het halverwege twee gehele getallen is, wordt het even getal geretourneerd. Dat wil gezegd: 4,5 wordt geconverteerd naar 4 en 5,5 wordt geconverteerd naar 6.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt een Byte waarde geconverteerd naar een Double en een Double waarde naar een Byte.

public void ConvertDoubleByte(double doubleVal) {
    byte	byteVal = 0;

    // Double to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(doubleVal);
        System.Console.WriteLine("{0} as a byte is: {1}.",
            doubleVal, byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "Overflow in double-to-byte conversion.");
    }

    // Byte to double conversion cannot overflow.
    doubleVal = System.Convert.ToDouble(byteVal);
    System.Console.WriteLine("{0} as a double is: {1}.",
        byteVal, doubleVal);
}

let convertDoubleByte (doubleVal: float) =
    // Double to byte conversion can overflow.
    try
        let byteVal = Convert.ToByte doubleVal
        printfn $"{doubleVal} as a byte is: {byteVal}."
        
        // Byte to double conversion cannot overflow.
        let doubleVal = Convert.ToDouble byteVal
        printfn $"{byteVal} as a double is: {doubleVal}."
    with :? OverflowException ->
        printfn "Overflow in double-to-byte conversion."

Public Sub ConvertDoubleByte(ByVal doubleVal As Double)
    Dim byteVal As Byte = 0

    ' Double to Byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(doubleVal)
        System.Console.WriteLine("{0} as a Byte is: {1}.", _
            doubleVal, byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in Double-to-Byte conversion.")
    End Try

    ' Byte to Double conversion cannot overflow.
    doubleVal = System.Convert.ToDouble(byteVal)
    System.Console.WriteLine("{0} as a Double is: {1}.", _
                              byteVal, doubleVal)
End Sub

Bron:

Convert.cs

Bron:

Convert.cs

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Convert.cs

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Convert.cs

Bron:

Convert.cs

public:
 static System::Byte ToByte(System::Object ^ value);

public static byte ToByte(object value);

public static byte ToByte(object? value);

static member ToByte : obj -> byte

Public Shared Function ToByte (value As Object) As Byte

Parameters

Retouren

Een 8-bits geheel getal zonder teken dat gelijk is aan value, of nul als value dat is null.

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt de ToByte(Object) methode gebruikt om een matrix met objecten te converteren naar Byte waarden.

object[] values = { true, -12, 163, 935, 'x', "104", "103.0", "-1",
                    "1.00e2", "One", 1.00e2};
byte result;
foreach (object value in values)
{
   try {
      result = Convert.ToByte(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        value.GetType().Name, value);
   }
   catch (FormatException)
   {
      Console.WriteLine("The {0} value {1} is not in a recognizable format.",
                        value.GetType().Name, value);
   }
   catch (InvalidCastException)
   {
      Console.WriteLine("No conversion to a Byte exists for the {0} value {1}.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//       Converted the Boolean value True to the Byte value 1.
//       The Int32 value -12 is outside the range of the Byte type.
//       Converted the Int32 value 163 to the Byte value 163.
//       The Int32 value 935 is outside the range of the Byte type.
//       Converted the Char value x to the Byte value 120.
//       Converted the String value 104 to the Byte value 104.
//       The String value 103.0 is not in a recognizable format.
//       The String value -1 is outside the range of the Byte type.
//       The String value 1.00e2 is not in a recognizable format.
//       The String value One is not in a recognizable format.
//       Converted the Double value 100 to the Byte value 100.

let values: obj[] = 
    [| true; -12; 163; 935; 'x'; "104"; "103.0" 
       "-1"; "1.00e2"; "One"; 1.00e2 |]
for value in values do
    try
        let result = Convert.ToByte value
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with
    | :? OverflowException ->
        printfn $"The {value.GetType().Name} value {value} is outside the range of the Byte type."
    | :? FormatException ->
        printfn $"The {value.GetType().Name} value {value} is not in a recognizable format."
    | :? InvalidCastException ->
        printfn $"No conversion to a Byte exists for the {value.GetType().Name} value {value}."
// The example displays the following output:
//       Converted the Boolean value True to the Byte value 1.
//       The Int32 value -12 is outside the range of the Byte type.
//       Converted the Int32 value 163 to the Byte value 163.
//       The Int32 value 935 is outside the range of the Byte type.
//       Converted the Char value x to the Byte value 120.
//       Converted the String value 104 to the Byte value 104.
//       The String value 103.0 is not in a recognizable format.
//       The String value -1 is outside the range of the Byte type.
//       The String value 1.00e2 is not in a recognizable format.
//       The String value One is not in a recognizable format.
//       Converted the Double value 100 to the Byte value 100.

Dim values() As Object = { True, -12, 163, 935, "x"c, "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2}
Dim result As Byte
For Each value As Object In values
   Try
      result = Convert.ToByte(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        value.GetType().Name, value)
   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not in a recognizable format.", _
                        value.GetType().Name, value)
   Catch e As InvalidCastException
      Console.WriteLine("No conversion to a Byte exists for the {0} value {1}.", _
                        value.GetType().Name, value)
                        
   End Try
Next                           
' The example displays the following output:
'       Converted the Boolean value True to the Byte value 1.
'       The Int32 value -12 is outside the range of the Byte type.
'       Converted the Int32 value 163 to the Byte value 163.
'       The Int32 value 935 is outside the range of the Byte type.
'       Converted the Char value x to the Byte value 120.
'       Converted the String value 104 to the Byte value 104.
'       The String value 103.0 is not in a recognizable format.
'       The String value -1 is outside the range of the Byte type.
'       The String value 1.00e2 is not in a recognizable format.
'       The String value One is not in a recognizable format.
'       Converted the Double value 100 to the Byte value 100.

Opmerkingen

Als value dat niet nullhet probleem is, verpakt deze methode een aanroep naar de IConvertible.ToByte implementatie van het onderliggende type value.