I am working on an application that relies strongly on a wcf request/callback pattern. That is, it uses a service which exposes a number of methods, and for each method there is a callback on which the result is returned.

In the client, I wish to open a modal dialog, make a request on the server and then wait for the result on the callback. But I never get a callback since the UI thread is blocked by the modal dialog.

Has anyone worked with a similar pattern? I would hate to have more threads in the client, and I also don't like the idea of 'simulating' a modal dialog.