问题
Hi there I am new to the windows phone development and I am trying to build a data driven application in which I have Created my BLL and EL and DAL ,which are all of windows phone class library type project. I have also an extra project of type class library in my solution in which I have added the Reference to "MyGeneration.dOOdads.dll" file . Now I want this project to be referenced in the windows phone app project.But when I try to add a reference ,The VS 2010 says...."Unable to add the selected project refernce.The project reference must be another silver light for windows phone project that is the same or the lower version ". . . . Kindly help me in this scenario. Thanks
回答1:
That can't and won't work. The phone runtime only has access to a timy subset (well, sort-of) of the full .NET libraries, so any non-phone-7 library is extremely unlikely to operate at all. To stop this surprising people, only libraries built against that runtime are allowed to be referenced.
If possible, create a new project with the same c# files, targeting the phone 7 framework. Now reference this project. It is quite likely that some bits will fail to compile (demonstrating the fact that it also wouldn't have run), which can be rectified in a number if ways (#if blocks, alternative .cs files, etc).
You might also have some luck by making the existing project a "portable class library" - this, however, is the most restrictive subset of all the common frameworks, and is even less likely to still compile (without changes).
Using the Portable Class Library project, you can build portable assemblies that work without modification on the .NET Framework, Silverlight, Windows Phone 7, or Xbox 360 platforms.
(from MSDN)
来源：https://stackoverflow.com/questions/11599293/how-to-add-external-non-windows-phone-class-library-project-reference-to-a-windo