Type.HasElementTypeImpl Methode
Definition
Wichtig
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Wenn die Eigenschaft in einer abgeleiteten Klasse überschrieben wird, wird die HasElementType Eigenschaft implementiert und bestimmt, ob der aktuelle Type Typ einen anderen Typ umfasst oder darauf verweist. Das heißt, ob es sich bei dem aktuellen Type Objekt um ein Array, einen Zeiger oder um einen Verweis handelt.
protected:
abstract bool HasElementTypeImpl();protected abstract bool HasElementTypeImpl();abstract member HasElementTypeImpl : unit -> boolProtected MustOverride Function HasElementTypeImpl () As BooleanGibt zurück
true wenn es sich Type um ein Array, einen Zeiger oder um einen Verweis handelt, andernfalls false.
Beispiele
Im folgenden Beispiel wird die Klasse MyTypeDelegatordefiniert, die die HasElementTypeImpl Methode überschreibt. Die Hauptklasse sucht nach der HasElementType Eigenschaft und zeigt den Elementtyp an.
using System;
using System.Reflection;
public class MyTypeDelegator : TypeDelegator
{
public string myElementType = null;
private Type myType = null ;
public MyTypeDelegator(Type myType) : base(myType)
{
this.myType = myType;
}
// Override Type.HasElementTypeImpl().
protected override bool HasElementTypeImpl()
{
// Determine whether the type is an array.
if(myType.IsArray)
{
myElementType = "array";
return true;
}
// Determine whether the type is a reference.
if(myType.IsByRef)
{
myElementType = "reference";
return true;
}
// Determine whether the type is a pointer.
if(myType.IsPointer)
{
myElementType = "pointer";
return true;
}
// Return false if the type is not a reference, array, or pointer type.
return false;
}
}
public class Type_HasElementTypeImpl
{
public static void Main()
{
try
{
int myInt = 0 ;
int[] myArray = new int[5];
MyTypeDelegator myType = new MyTypeDelegator(myArray.GetType());
// Determine whether myType is an array, pointer, reference type.
Console.WriteLine("\nDetermine whether a variable is an array, pointer, or reference type.\n");
if( myType.HasElementType)
Console.WriteLine("The type of myArray is {0}.", myType.myElementType);
else
Console.WriteLine("myArray is not an array, pointer, or reference type.");
myType = new MyTypeDelegator(myInt.GetType());
// Determine whether myType is an array, pointer, reference type.
if( myType.HasElementType)
Console.WriteLine("The type of myInt is {0}.", myType.myElementType);
else
Console.WriteLine("myInt is not an array, pointer, or reference type.");
}
catch( Exception e )
{
Console.WriteLine("Exception: {0}", e.Message);
}
}
}
open System.Reflection
type MyTypeDelegator(myType) =
inherit TypeDelegator(myType)
[<DefaultValue>]
val mutable public myElementType: string
// Override Type.HasElementTypeImpl().
override this.HasElementTypeImpl() =
// Determine whether the type is an array.
if myType.IsArray then
this.myElementType <- "array"
true
// Determine whether the type is a reference.
elif myType.IsByRef then
this.myElementType <- "reference"
true
// Determine whether the type is a pointer.
elif myType.IsPointer then
this.myElementType <- "pointer"
true
// Return false if the type is not a reference, array, or pointer type.
else false
try
let myInt = 0
let myArray = Array.zeroCreate<int> 5
let myType = MyTypeDelegator(myArray.GetType())
// Determine whether myType is an array, pointer, reference type.
printfn "\nDetermine whether a variable is an array, pointer, or reference type.\n"
if myType.HasElementType then
printfn $"The type of myArray is {myType.myElementType}."
else
printfn "myArray is not an array, pointer, or reference type."
let myType = MyTypeDelegator(myInt.GetType())
// Determine whether myType is an array, pointer, reference type.
if myType.HasElementType then
printfn $"The type of myInt is {myType.myElementType}."
else
printfn "myInt is not an array, pointer, or reference type."
with e ->
printfn $"Exception: {e.Message}"
Imports System.Reflection
Public Class MyTypeDelegator
Inherits TypeDelegator
Public myElementType As String = Nothing
Private myType As Type = Nothing
Public Sub New(ByVal myType As Type)
MyBase.New(myType)
Me.myType = myType
End Sub
' Override Type.HasElementTypeImpl().
Protected Overrides Function HasElementTypeImpl() As Boolean
' Determine whether the type is an array.
If myType.IsArray Then
myElementType = "array"
Return True
End If
' Determine whether the type is a reference.
If myType.IsByRef Then
myElementType = "reference"
Return True
End If
' Determine whether the type is a pointer.
If myType.IsPointer Then
myElementType = "pointer"
Return True
End If
' The type is not a reference, array, or pointer type.
Return False
End Function 'HasElementTypeImpl
End Class
Public Class Type_HasElementTypeImpl
Public Shared Sub Main()
Try
Dim myInt As Integer = 0
Dim myArray(4) As Integer
Dim myType As New MyTypeDelegator(myArray.GetType())
Console.WriteLine(ControlChars.NewLine + "Determine whether a variable refers to an array or pointer or reference type." + ControlChars.NewLine)
' Determine whether myType is an array, pointer, reference type.
If myType.HasElementType Then
Console.WriteLine("The type of myArray is {0}.", myType.myElementType.ToString())
Else
Console.WriteLine("myArray is not an array, pointer, or reference type.")
End If
myType = New MyTypeDelegator(myInt.GetType())
' Determine whether myType is an array, pointer, reference type.
If myType.HasElementType Then
Console.WriteLine("The type of myInt is {0}.", myType.myElementType.ToString())
Else
Console.WriteLine("myInt is not an array, pointer, or reference type.")
End If
Catch e As Exception
Console.WriteLine("Exception: {0}", e.Message.ToString())
End Try
End Sub
End Class
Hinweise
Beispiel: Type.GetType("Int32[]"). HasElementTypeImpl gibt zurück true, aber Type.GetType("Int32"). HasElementTypeImpl gibt zurück false. HasElementTypeImpl gibt auch für "Int32*" und "Int32&" zurück true .
