Type.HasElementTypeImpl メソッド

[アーティクル]
03/28/2008

派生クラスによってオーバーライドされた場合、 HasElementType プロパティを実装し、現在の Type が別の型を包含または参照しているかどうか、つまり現在の Type が配列やポインタであるか、参照渡しかどうかを判断します。

Protected MustOverride Function HasElementTypeImpl() As Boolean
[C#]
protected abstract bool HasElementTypeImpl();
[C++]
protected: virtual bool HasElementTypeImpl() = 0;
[JScript]
protected abstract function HasElementTypeImpl() : Boolean;

戻り値

Type が配列やポインタであるか、参照渡しである場合は true 。それ以外の場合は false 。

解説

たとえば、Type.GetType("Int32[]").HasElementTypeImpl は true を返しますが、Type.GetType("Int32").HasElementTypeImpl は false を返します。HasElementTypeImpl は、"Int32*" と "Int32&" のどちらに対しても true を返します。

使用例

[Visual Basic, C#, C++] HasElementTypeImpl メソッドをオーバーライドした MyTypeDelegator クラスを定義する例を次に示します。メインのクラスは、 HasElementType プロパティをチェックして、要素の型を表示します。

 
Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic
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 'New
    ' 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 'MyTypeDelegator
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 'Main
End Class 'Type_HasElementTypeImpl

[C#] 
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);
        }
    }
}

[C++] 
#using <mscorlib.dll>

using namespace System;
using namespace System::Reflection;
public __gc class MyTypeDelegator : public TypeDelegator {
public:
   String* myElementType;
private:
   Type* myType;
public:
   MyTypeDelegator(Type* myType) : TypeDelegator(myType) {
      this->myType = myType;
   }
   // Override Type::HasElementTypeImpl().
protected:
   bool HasElementTypeImpl() {
      // Determine whether the type is an array.
      if (myType->IsArray) {
         myElementType = S"array";
         return true;
      }
      // Determine whether the type is a reference.
      if (myType->IsByRef) {
         myElementType = S"reference";
         return true;
      }
      // Determine whether the type is a pointer.
      if (myType->IsPointer) {
         myElementType = S"pointer";
         return true;
      }
      // Return false if the type is not a reference, array, or pointer type.
      return false;
   }
};

int main() {
   try {
      int myInt = 0 ;
      Int32 myArray[] = new Int32[5];
      MyTypeDelegator* myType = new MyTypeDelegator(myArray->GetType());
      // Determine whether myType is an array, pointer, reference type.
      Console::WriteLine(S"\nDetermine whether a variable is an array, pointer, or reference type.\n");
      if (myType->HasElementType)
         Console::WriteLine(S"The type of myArray is {0}.", myType->myElementType);
      else
         Console::WriteLine(S"myArray is not an array, pointer, or reference type.");
      myType = new MyTypeDelegator(__box(myInt)->GetType());
      // Determine whether myType is an array, pointer, reference type.
      if (myType->HasElementType)
         Console::WriteLine(S"The type of myInt is {0}.", myType->myElementType);
      else
         Console::WriteLine(S"myInt is not an array, pointer, or reference type.");
   } catch (Exception* e) {
      Console::WriteLine(S"Exception: {0}", e->Message);
   }
}

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必要条件

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard

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Type.HasElementTypeImpl メソッド

戻り値

解説

使用例

必要条件

参照

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