ObjectHandle Class
Wraps marshal-by-value object references, allowing them to be returned through an indirection.
Assembly: mscorlib (in mscorlib.dll)
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()) Console.WriteLine("") 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()) 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 'Main End Class 'Test
#using <mscorlib.dll>
using namespace System;
using namespace System::Runtime::Remoting;
public __gc class MyType : public MarshalByRefObject {
public:
MyType() {
Console::Write(S"Created an instance of MyType in an AppDomain with the ");
Console::WriteLine(S"hash code {0}", __box( AppDomain::CurrentDomain->GetHashCode()));
Console::WriteLine(S"");
}
public:
int GetAppDomainHashCode() {
return AppDomain::CurrentDomain->GetHashCode();
}
};
int main() {
Console::WriteLine(S"The hash code of the default AppDomain is {0}.",
__box( AppDomain::CurrentDomain->GetHashCode()));
Console::WriteLine(S"");
// Creates another AppDomain.
AppDomain* domain = AppDomain::CreateDomain(S"AnotherDomain",
0,
(AppDomainSetup*)0);
// Creates an instance of MyType defined in the assembly called ObjectHandleAssembly.
ObjectHandle* obj = domain->CreateInstance(S"ObjectHandleAssembly", S"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(S"The unwrapped object is a proxy.");
else
Console::WriteLine(S"The unwrapped object is not a proxy!");
Console::WriteLine(S"");
Console::Write(S"Calling a method on the object located in an AppDomain with the hash code ");
Console::WriteLine(testObj->GetAppDomainHashCode());
}
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.