FieldInfo.FieldHandle Propriété

Définition

Espace de noms:

System.Reflection

Assembly:

System.Runtime.dll

Source:

FieldInfo.CoreCLR.cs

Obtient RuntimeFieldHandle qui est un handle vers la représentation interne des métadonnées d'un champ.

public:
 abstract property RuntimeFieldHandle FieldHandle { RuntimeFieldHandle get(); };

public abstract RuntimeFieldHandle FieldHandle { get; }

member this.FieldHandle : RuntimeFieldHandle

Public MustOverride ReadOnly Property FieldHandle As RuntimeFieldHandle

Valeur de propriété

RuntimeFieldHandle

Handle vers la représentation interne des métadonnées d'un champ.

Exemples

L’exemple suivant récupère les informations de champ MyClass.MyField et affiche le champ associé au handle de champ.

using namespace System;
using namespace System::Reflection;

public ref class MyClass
{
public:
   String^ MyField;
};

void DisplayFieldHandle( RuntimeFieldHandle myFieldHandle )
{
   // Get the type from the handle.
   FieldInfo^ myField = FieldInfo::GetFieldFromHandle( myFieldHandle );

   // Display the type.
   Console::WriteLine( "\nDisplaying the field from the handle.\n" );
   Console::WriteLine( "The type is {0}.", myField );
}

int main()
{
   MyClass^ myClass = gcnew MyClass;

   // Get the type of MyClass.
   Type^ myType = MyClass::typeid;
   try
   {
      // Get the field information of MyField.
      FieldInfo^ myFieldInfo = myType->GetField( "MyField", static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Instance) );

      // Determine whether or not the FieldInfo Object* is 0.
      if ( myFieldInfo != nullptr )
      {
         // Get the handle for the field.
         RuntimeFieldHandle myFieldHandle = myFieldInfo->FieldHandle;
         DisplayFieldHandle( myFieldHandle );
      }
      else
      {
         Console::WriteLine( "The myFieldInfo Object* is 0." );
      }
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "Exception: {0}", e->Message );
   }
}

using System;
using System.Reflection;

public class MyClass
{
    public string MyField = "Microsoft";
}

public class FieldInfo_FieldHandle
{
    public static void Main()
    {

        MyClass myClass =new MyClass();

        // Get the type of MyClass.
        Type myType = typeof(MyClass);

        try
        {
            // Get the field information of MyField.
            FieldInfo myFieldInfo = myType.GetField("MyField", BindingFlags.Public
                | BindingFlags.Instance);

            // Determine whether or not the FieldInfo object is null.
            if(myFieldInfo!=null)
            {
                // Get the handle for the field.
                RuntimeFieldHandle myFieldHandle=myFieldInfo.FieldHandle;

                DisplayFieldHandle(myFieldHandle);
            }
            else
            {
                Console.WriteLine("The myFieldInfo object is null.");
            }
        }
        catch(Exception e)
        {
            Console.WriteLine("Exception: {0}", e.Message);
        }
    }

    public static void DisplayFieldHandle(RuntimeFieldHandle myFieldHandle)
    {
        // Get the type from the handle.
        FieldInfo myField = FieldInfo.GetFieldFromHandle(myFieldHandle);

        // Display the type.
        Console.WriteLine("\nDisplaying the field from the handle.\n");
        Console.WriteLine("The type is {0}.", myField.ToString());
    }
}

Imports System.Reflection

Public Class [MyClass]
    Public MyField As String = "Microsoft"
End Class

Public Class FieldInfo_FieldHandle
    Public Shared Sub Main()
        Dim [myClass] As New [MyClass]()
        ' Get the type of MyClass.
        Dim myType As Type = GetType([MyClass])
        Try
            ' Get the field information of MyField.
            Dim myFieldInfo As FieldInfo = myType.GetField("MyField", BindingFlags.Public Or BindingFlags.Instance)

            ' Determine whether or not the FieldInfo object is null.
            If Not (myFieldInfo Is Nothing) Then
                ' Get the handle for the field.
                Dim myFieldHandle As RuntimeFieldHandle = myFieldInfo.FieldHandle

                DisplayFieldHandle(myFieldHandle)
            Else
                Console.WriteLine("The myFieldInfo object is null.")
            End If
        Catch e As Exception
            Console.WriteLine(" Exception: {0}", e.Message.ToString())
        End Try
    End Sub

    Public Shared Sub DisplayFieldHandle(ByVal myFieldHandle As RuntimeFieldHandle)
        ' Get the type from the handle.
        Dim myField As FieldInfo = FieldInfo.GetFieldFromHandle(myFieldHandle)
        ' Display the type.
        Console.WriteLine(ControlChars.Cr + "Displaying the field from the handle." + ControlChars.Cr)
        Console.WriteLine("The type is {0}.", myField.ToString())
    End Sub
End Class

Remarques

Les handles sont valides uniquement dans le domaine d’application dans lequel ils ont été obtenus.