I am trying to do the same (add a C# class library reference to a silverlight project) where can I find this Link to File option? 

dsdsico

I'm looking for a way as well to share a Class Library with both a Silverlight project as well as a Windows Forms application. I tried creating a Silverlight class library, because I thought that, since Silverlight uses a subset of the full .NET framework, a Windows Forms application should be able to use this Silverlight Class Library. But that doesn't quite work.

I guess we could share the C# source files between the Silverlight project and the Full .NET project using the Link to file option when adding a C# file to the project...