VS2010 - Getting "type or namespace name could not be found" but everything seems ok?

Question

I'm getting a "type or namespace name could not be found" error for a C# WPF app in VS2010. This area of code was compiling fine, but suddenly I'm getting this error. I've tried removing the Project Reference and Using statement, shutting VS2010 and restarting, but still I have this issue.

Any ideas why this might be occurring, where it seems like I'm doing the write thing re Reference & Using statement?

I also noted in VS2010 that intellisense for that namespace is working ok, so it seems like VS2010 has the project reference and seeing the namespace on one hand, but during compile doesn't see it?

Answer 1

First I would verify that your project's generated information isn't corrupt. Do a clean and rebuild on your solution.

If that doesn't help, one thing I've seen work in the past for designer issues is opening up a windows forms project, then closing it again. This is a little chicken-entrails-ish, though, so don't hold your breath.

Answer 2

It may work to close and restart Visual Studio. It sometimes seems to get "Stuck"

Answer 3

You might also try eliminating the code you think you're having problems with and seeing if it compiles with no references to that code. If not, fix things until it compiles again, and then work your suspected problem code back in. Sometimes I get strange errors about classes or methods that I know are correct when the compiler doesn't like something else. Once I fix the thing that it's really getting hung up on, these 'phantom' errors disappear.

Answer 4

I have seen this behaviour when an application is set to target the .Net 4 Client Profile framework, and the project it references targets the full .Net 4 framework.

The solution in this case is to either upgrade the framework target of the application, or downgrade the target of referenced assembly. I have not seen it mentioned explicitly anywhere, but from what i have seen it is okay for a full framework app to reference/consume a client profile framework assembly, but not the other way round (client profile cannot reference full framework targeted assembly).