WPF/C# can't find valid assembly reference

Question

I've downloaded an open source third-party assembly for use in my WPF/.NET 4/VS2010 project. I've added a reference to the project's DLL and verified that VS2010 can see it by walking through the exposed classes in the object browser. When I add a "using" directive to the appropriate class in my project, Intellisense offers the new assembly as a suggestion, so VS2010 is aware of it at some level. Intellisense also generates tips for the exposed classes that I'm trying to use. Unfortunately, my project fails to compile because of a missing assembly reference for this assembly. The classes are highlighted as valid, Intellisense lets me navigate to the methods, etc, but the compiler won't acknowledge them. In case it was a C# version mismatch, I recompiled the open source project, targeting .NET 4. This didn't change a thing.

What am I missing? This seems like simple developer error, but I'm not sure how to proceed.

Answer 1

This sometimes happens when the library itself depends on other libraries. When your library contains multiple DLL's, reference all the DLL's of that library in your project.