Type.HasElementTypeImpl Method

Reference

Definition

Namespace:: System

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Type.cs

Source:: Type.cs

Source:: Type.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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 -> bool

Protected MustOverride Function HasElementTypeImpl () As Boolean

Returns

Boolean

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 namespace System;
using namespace System::Reflection;
public ref class MyTypeDelegator: public TypeDelegator
{
public:
   String^ myElementType;

private:
   Type^ myType;

public:
   MyTypeDelegator( Type^ myType )
      : TypeDelegator( myType )
   {
      this->myType = myType;
   }


protected:

   // Override Type::HasElementTypeImpl().
   virtual bool HasElementTypeImpl() override
   {
      
      // 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;
   }

};

int main()
{
   try
   {
      int myInt = 0;
      array<Int32>^myArray = gcnew array<Int32>(5);
      MyTypeDelegator^ myType = gcnew 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 = gcnew 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 );
   }

}

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&".

Applies to

مشاركة عبر