Common source code for compact and full framework for DLL?

I am trying to write a DLL that will run on either the compact or full
framework in VS 2008.  I'd like to be able to code and test on a desktop
initially, then move the code to a mobile device for testing on that platform.

I thought it would be as easy as changing the target device and recompiling,
but once selected as CF I do not have the option of going back.

I assume I am not the first to want to do this.  How is this being done by
others?

Never mind... I am an idiot and found the answer right after I posted.

Never mind... I am an idiot and found the answer right after I posted.

And, for those of us reading the thread with interest, could you please

And, for those of us reading the thread with interest, could you please post
the "right answer" you found?

Thanks!