Created attachment 436994 [details]
Example Application To Reproduce

Description of Problem:

I hesitated to post this report because the problem occurs in really the -MOST- basic usage of a duplex WCF service that I can fathom, and this has reportedly been supported for several versions. I am entirely open to the idea that my energy drink had some kind of hallucinogen in it.

As of Mono 2.10.2, I cannot successfully implement a duplex WCF client/server. The client fails to initialize when attempting to create the underlying communication channel. The error is an InvalidCastException thrown during ClientBase<T>.CreateChannel().

I have isolated this problem to DuplexClientBase<T>, as I can successfully initialize a simplex client using ClientBase<T>, as well as manually create the channel by calling DuplexChannelFactory<T>.CreateChannel() and bypassing the DuplexClientBase<T> helper all together.


Steps to reproduce the problem:
I have provided a very basic example:

* A service contract (ITestContract) which defines a single addition operation, and is associated with a callback contract (ITestCallbackContract)
* A callback contract (ITestCallbackContract) that defines a simple operation to send a message back to the client side.
* An implementation of the server (TestServer) and the callback object (TestCallbackClient)

The setup is dead simple. net-tcp binding, bound to local interface on port 15201.



Actual Results:
Unhandled Exception: System.InvalidCastException: Cannot cast from source type to destination type.
  at System.ServiceModel.ClientBase`1[Jgh.Test.Program+ITestContract].get_InnerChannel () [0x00000] in <filename unknown>:0
  at System.ServiceModel.ClientBase`1[Jgh.Test.Program+ITestContract].Open () [0x00000] in <filename unknown>:0
  at Jgh.Test.Program.Main (System.String[] args) [0x00000] in <filename unknown>:0

Expected Results:
Callback says: Adding 50 and 25 is 75!
Adding server result: 75

How often does this happen? 

This examples works out of box on .NET, but fails identically with Mono 2.10.2 on both Windows 7 x64 and OpenSUSE 11.4 x86-64. I have not tested other platforms or other mono versions.

Additional Information: