FieldInfo.FieldHandle Proprietà

Definizione

Spazio dei nomi:

System.Reflection

Assembly:

System.Runtime.dll

Assembly:

netstandard.dll

Assembly:

mscorlib.dll

Ottiene un oggetto RuntimeFieldHandle, che è un handle della rappresentazione dei metadati interni di un campo.

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

public abstract RuntimeFieldHandle FieldHandle { get; }

member this.FieldHandle : RuntimeFieldHandle

Public MustOverride ReadOnly Property FieldHandle As RuntimeFieldHandle

Valore della proprietà

RuntimeFieldHandle

Handle per la rappresentazione dei metadati interni di un campo.

Implementazioni

FieldHandle

Esempio

Nell'esempio seguente vengono recuperate le informazioni sul campo MyClass.MyField e viene visualizzato il campo associato all'handle di campo.

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

Commenti

Gli handle sono validi solo nel dominio applicazione in cui sono stati ottenuti.