I can't include classes in ASP.NET projects.

I put the class 'MyClass' with the namespace 'mynamespace' in the App_Code folder which is suggested by Visual Studio.

In Default.aspx a have 'using mynamespace;'. Visual Studio makes some sort of connection because when a write MyClass and hits dot I see all classes in the dropdown help box.

There's no problem building the project but when a browse to the web site a get:

Compiler Error Message: CS0246: The type or namespace name 'mynamespace' could not be found (are you missing a using directive or an assembly reference?)

I also tried "Add existing  item..." and choosing 'MyClass' but it didn't help either.

Please, help me.