Marshal.GetIDispatchForObject

Does anyone know if it is possible to create an IDispatch pointer out of a C# class to pass to a C++ object expecting an IDispatch pointer? I assume I have to create an interface, but how do I pass that interface as a pointer?

Code:

// C++ Executable expecting a COM IDispatch pointer CCOW.ContextManager cm = new CCOW.ContextManager() // C# dll ContextParticipant .ContextParticipant icp = new ContextParticipant .ContextParticipant(); IntPtr iDispatchPtr = Marshal.GetIDispatchForObject(icp); cm.JoinCommonContext(iDispatchPtr);

When I execute the above code the iDispatchPtr contains a value when running in debug, but when I try to use it in the C++ control it becomes NULL.

Any thoughts?

Thanks in advance!