I have a WPF/ASP.NET project which I haven’t worked on for a while (ResourceBlender.NET – http://resourceblender.codeplex.com/). The project contains a DataLayer and a Core layer, these are both used by the WPF application and ASP.NET project in the solution.
If the WPF project is set as the startup project and I try to build the application, I get “The type or namespace name ‘whatever’ could not be found (are you missing a using directive or an assembly reference?)”.
The error list shows these when I try to build, run or debug, but double clicking and going to the error shows no actual errors in the editor and everything is highlighted as normal.
The ASP.NET project builds fine. I’m absolutely clueless on this one, as there are no obvious errors to fix – could it be metadata somewhere?
Check that all assemblies does not target the 3.5/4.0 Client Profile (It is probably the WPF application that is the culprit). This will cause exactly the error message you’re describing.