Not long ago I was trying to port an application from Silverlight 3 to the Silverlight variant used in Windows Phone 7 Series. I thought I had run into an obstacle when I realized that a piece of functionality that I was using was actually implemented by a third party and there wasn't a WP7S version. So I decided to try to use the library anyway and it worked! Earlier this week I cam across a message in a post in the MSDN forums by Shawn Oster that states some of the requirements for sharing code between Silverlight 3 and WP7S.
- The Class Library must be based off of Silverlight 3, not 4
- Don't reference Windows Phone specific controls in the library
- Don't reference System.Windows.Browsers (it's desktop specific)
- Don't use IQueryable (it's not in WP7S)