FieldInfo.FieldHandle Property

Definition

Namespace:

System.Reflection

Assembly:

System.Runtime.dll

Source:

FieldInfo.CoreCLR.cs

Gets a RuntimeFieldHandle, which is a handle to the internal metadata representation of a field.

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

public abstract RuntimeFieldHandle FieldHandle { get; }

member this.FieldHandle : RuntimeFieldHandle

Public MustOverride ReadOnly Property FieldHandle As RuntimeFieldHandle

Property Value

RuntimeFieldHandle

A handle to the internal metadata representation of a field.

Examples

The following example retrieves MyClass.MyField field information and displays the field associated with the field handle.

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

Remarks

The handles are valid only in the appdomain in which they were obtained.