The type or namespace name could not be found [duplicate]

Answer 1

If your project (PrjTest) does not expose any public types within the PrjTest namespace, it will cause that error.

Does the project (PrjTest) include any classes or types in the "PrjTest" namespace which are public?

Answer 2

See this question.

Turns out this was a client profiling issue.

PrjForm was set to ".Net Framework 4 Client Profile" I changed it to ".Net Framework 4", and now I have a successful build.

Thanks everyone! I guess it figures that after all that time spent searching online, I find the solution minutes after posting, I guess the trick is knowing the right question to ask..

Answer 3

The using statement refers to a namespace, not a project.

Make sure that you have the appropriately named namespace in your referenced project:

namespace PrjTest
{
     public class Foo
     {
          // etc...
     }
}

Read more about namespaces on MSDN:

• Using Namespaces

Answer 4

I encountered this issue it turned out to be.

Project B references Project A.

Project A compiled as A.dll (assembly name = A).

Project B compiled as A.dll (assembly name A).

Visual Studio 2010 wasn't catching this. Resharper was okay, but wouldn't compile. WinForms designer gave misleading error message saying likely resulting from incompatbile platform targets.

The solution, after a painful day, was to make sure assemblies don't have same name.

Answer 5

In my case I had:

Referenced DLL : .NET 4.5

Project : .NET 4.0

Because of the above mismatch, the 4.0 project couldn't see inside the namespace of the 4.5 .DLL. I recompiled the .DLL to target .NET 4.0 and I was fine.

Answer 6

The compiled dll should have public Class.