problem using self built DLL

I made an MFC extension DLL, but I couldn't get it working on the
client application. Can somebody please tell me what I did wrong in
the procedure:

1. I started an MFC extension DLL project called "MyDll". I added a
class called "MyClass" and added the keyword AFX_EXT_CLASS in the
class declaration in the header file.

2. I built the project and copied the files "MyDll.dll" and
"MyDll.lib" to the client project folder.

3. In the client project settings, I added the file MyDll.lib in the
linker - input section.

4. I made a MyDll.h file with the line: class AFX_EXT_CLASS MyClass;

5. I used #include "MyDll.h" in the cpp files where I need MyClass.

With the above steps, I expect MyClass to be defined. But when I use
the imported class it gave me the error:

error C2079: 'CClientApp::myobject' uses undefined class 'MyClass'


Please advise.

.