WorkflowServices don't provide a way to implement a contract, but that doesn't mean you can't get them to look like they do. This is useful if you want to create a client proxy using a ChannelFactory. In this episode, I'll show you what I learned about
the messaging activities to make this work.
I also wrote this up on my blog.
How to make a WorkflowService implement a contract
Sample Code (MSDN Code Gallery)