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ObjectHandle Class

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


Namespace:  System.Runtime.Remoting
Assembly:  mscorlib (in mscorlib.dll)

<ClassInterfaceAttribute(ClassInterfaceType.AutoDual)> _
<ComVisibleAttribute(True)> _
Public Class ObjectHandle _
	Inherits MarshalByRefObject _
	Implements IObjectHandle

The ObjectHandle type exposes the following members.

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

Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeLifetimeServiceInitializes the lifetime lease of the wrapped object. (Overrides MarshalByRefObject.InitializeLifetimeService.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodMemberwiseClone(Boolean)Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodUnwrapReturns the wrapped object.

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.

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".

Imports System
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())
   End Sub 'New 

   Public Function GetAppDomainHashCode() As Integer 
      Return AppDomain.CurrentDomain.GetHashCode()
   End Function 'GetAppDomainHashCode

End Class 'MyType

Class Test

   Public Shared Sub Main()

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

      ' 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.")
         Console.WriteLine("The unwrapped object is not a proxy!")
      End If 
      Console.Write("Calling a method on the object located in an AppDomain with the hash code ")

   End Sub 'Main 

End Class 'Test 

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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