Type.HasElementTypeImpl Method
Definition
Important
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When overridden in a derived class, implements the HasElementType property and determines whether the current Type encompasses or refers to another type; that is, whether the current Type is an array, a pointer, or is passed by reference.
protected:
abstract bool HasElementTypeImpl();protected abstract bool HasElementTypeImpl();abstract member HasElementTypeImpl : unit -> boolProtected MustOverride Function HasElementTypeImpl () As BooleanReturns
true if the Type is an array, a pointer, or is passed by reference; otherwise, false.
Examples
The following example defines the class MyTypeDelegator, which overrides the HasElementTypeImpl method. The main class checks for the HasElementType property and displays the element type.
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
Remarks
For example, Type.GetType("Int32[]").HasElementTypeImpl returns true, but Type.GetType("Int32").HasElementTypeImpl returns false. HasElementTypeImpl also returns true for "Int32*" and "Int32&".
