Extending and fixing MCE

What you can do if you want to change some functional behaviour of MCE (Media Center application) or add some more functionality there? Or what you can do if you need to fix some 2 or 10 foot UI issues of the Media Center app?

Well, the only way I could come up with is - a global hook or Dll-injection. There are a few techniques known in Win32 world (I wish those exist in Windows CE as well :-) ) how to do the Dll injections (from writing to another process address space to the supported global hooks). Despite the fact that it may be a dangerous implementation (stability issues, lowering security, etc.) this is the only way that seems viable. Two main reasons:
- to have a better and faster implementation for your own monitoring agent application you'd probably want to stick to C/C++ to easier the access to Win32 APIs (P-Invoke's are costly and require lots of coding for missing header). MCE SDK doesn't allow you to write add-ins in native C++. (or perhaps it does but I didn't investigate this deep enough)
- too many limitations there on background add-ins for Vista MCE. You will always lose the MCE launch moment and some other events as well.

I have implemented a MCE hook-up agent that keeps monitoring the Media Center app on a complex of things - messages, windows, positions, etc. - including WM_INPUT (raw input messages), keyboard and mouse messages and etc.

A piece of advice - if you are playing with MCE on Vista, try to stay away from a service implementation for your app. On Vista, services are running in a separate, isolated Windows session (session 0) and it may take you an effort to implement the cross-session interface between your hook into MCE and the service. (not impossible but just over-complicates the implementation)