I have a WPF application with a group of asynchronous WCF service calls all mashed into the code behind, complete with event handlers and everything, that I have to refactor to productionize and maintain. I want to separate concerns here for maintainability and all the other good reasons to do this, but I'm not sure exactly how to achieve this. Anybody have any good ideas on how to do this, or at least some links to put me in the right direction? My thinking: Create an "infrastructure" layer and reference the services there. Move the asynchronous event handlers into this layer. When an update is called, I will bubble up my own event with my own derivation of the EventArgs class that contains the data the UI will need. I'll have a fairly coupled hooking of the UI to the infrastructure layer as it will consume events I fire off upon completion of an asynchronous data call.