ObjectHandle Class

Definition

Namespace:

System.Runtime.Remoting

Assembly:

System.Runtime.dll

Source:

ObjectHandle.cs

Wraps marshal-by-value object references, allowing them to be returned through an indirection.

public ref class ObjectHandle : MarshalByRefObject

public class ObjectHandle : MarshalByRefObject

type ObjectHandle = class
    inherit MarshalByRefObject

Public Class ObjectHandle
Inherits MarshalByRefObject

Inheritance

Object

MarshalByRefObject

ObjectHandle

Examples

The following code example shows how to create an object in another AppDomain, and retrieve a proxy to the object from a ObjectHandle. In this example, you can assume that the code of the MyType class is compiled into an assembly called "ObjectHandleAssembly".

using namespace System;
using namespace System::Runtime::Remoting;
public ref class MyType: public MarshalByRefObject
{
public:
   MyType()
   {
      Console::Write( "Created an instance of MyType in an AppDomain with the " );
      Console::WriteLine( "hash code {0}", AppDomain::CurrentDomain->GetHashCode() );
      Console::WriteLine( "" );
   }

   int GetAppDomainHashCode()
   {
      return AppDomain::CurrentDomain->GetHashCode();
   }

};

int main()
{
   Console::WriteLine( "The hash code of the default AppDomain is {0}.", AppDomain::CurrentDomain->GetHashCode() );
   Console::WriteLine( "" );
   
   // Creates another AppDomain.
   AppDomain^ domain = AppDomain::CreateDomain( "AnotherDomain", nullptr, (AppDomainSetup^)nullptr );
   
   // Creates an instance of MyType defined in the assembly called ObjectHandleAssembly.
   ObjectHandle^ obj = domain->CreateInstance( "ObjectHandleAssembly", "MyType" );
   
   // Unwraps the proxy to the MyType object created in the other AppDomain.
   MyType^ testObj = dynamic_cast<MyType^>(obj->Unwrap());
   if ( RemotingServices::IsTransparentProxy( testObj ) )
      Console::WriteLine( "The unwrapped object is a proxy." );
   else
      Console::WriteLine( "The unwrapped object is not a proxy!" );

   Console::WriteLine( "" );
   Console::Write( "Calling a method on the object located in an AppDomain with the hash code " );
   Console::WriteLine( testObj->GetAppDomainHashCode() );
   
}

using System;
using System.Runtime.Remoting;

public class MyType : MarshalByRefObject {

   public MyType()  {
      Console.Write("Created an instance of MyType in an AppDomain with the ");
      Console.WriteLine("hash code {0}",AppDomain.CurrentDomain.GetHashCode());
      Console.WriteLine("");
   }

   public int GetAppDomainHashCode() {
      return AppDomain.CurrentDomain.GetHashCode();
   }
}

class Test {

   public static void Main() {

      Console.WriteLine("The hash code of the default AppDomain is {0}.",
                        AppDomain.CurrentDomain.GetHashCode());
      Console.WriteLine("");

      // Creates another AppDomain.
      AppDomain domain = AppDomain.CreateDomain("AnotherDomain",
                                                null,
                                                (AppDomainSetup)null);

      // Creates an instance of MyType defined in the assembly called ObjectHandleAssembly.
      ObjectHandle obj = domain.CreateInstance("ObjectHandleAssembly", "MyType");

      // Unwrapps the proxy to the MyType object created in the other AppDomain.
      MyType testObj = (MyType)obj.Unwrap();

      if(RemotingServices.IsTransparentProxy(testObj))
         Console.WriteLine("The unwrapped object is a proxy.");
      else
         Console.WriteLine("The unwrapped object is not a proxy!");

      Console.WriteLine("");
      Console.Write("Calling a method on the object located in an AppDomain with the hash code ");
      Console.WriteLine(testObj.GetAppDomainHashCode());
   }
}

Imports System.Runtime.Remoting


Public Class MyType
   Inherits MarshalByRefObject
      
   Public Sub New()
      Console.Write("Created an instance of MyType in an AppDomain with the ")
      Console.WriteLine("hashcode {0}", AppDomain.CurrentDomain.GetHashCode())
      Console.WriteLine("")
   End Sub
   
   
   Public Function GetAppDomainHashCode() As Integer
      Return AppDomain.CurrentDomain.GetHashCode()
   End Function 'GetAppDomainHashCode

End Class


Class Test
     
   Public Shared Sub Main()
      
      Console.WriteLine("The hash code of the default AppDomain is {0}.", AppDomain.CurrentDomain.GetHashCode())
      Console.WriteLine("")
      
      ' Creates another AppDomain.
      Dim domain As AppDomain = AppDomain.CreateDomain("AnotherDomain", Nothing, CType(Nothing, AppDomainSetup))
      
      ' Creates an instance of MyType defined in the assembly called ObjectHandleAssembly.
      Dim obj As ObjectHandle = domain.CreateInstance("ObjectHandleAssembly", "MyType")
      
      ' Unwrapps the proxy to the MyType object created in the other AppDomain.
      Dim testObj As MyType = CType(obj.Unwrap(), MyType)
      
      If RemotingServices.IsTransparentProxy(testObj) Then
         Console.WriteLine("The unwrapped object is a proxy.")
      Else
         Console.WriteLine("The unwrapped object is not a proxy!")
      End If 
      Console.WriteLine("")
      Console.Write("Calling a method on the object located in an AppDomain with the hash code ")
      Console.WriteLine(testObj.GetAppDomainHashCode())

   End Sub

End Class

Remarks

The ObjectHandle class is used to pass an object (in a wrapped state) between multiple application domains without loading the metadata for the wrapped object in each AppDomain through which the ObjectHandle travels. Thus, the ObjectHandle class gives the caller control of when the Type of the remote object is loaded into a domain.

Constructors

ObjectHandle(Object)

Initializes an instance of the ObjectHandle class, wrapping the given object o.

Methods

CreateObjRef(Type)	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject)
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetLifetimeService()	Obsolete. Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject)
GetType()	Gets the Type of the current instance. (Inherited from Object)
InitializeLifetimeService()	Obsolete. Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
MemberwiseClone(Boolean)	Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject)
ToString()	Returns a string that represents the current object. (Inherited from Object)
Unwrap()	Returns the wrapped object.