Cannot implement interface because '<element>' cannot be found
Class Designer could not implement the interface because the code element that you entered either does not exist or is not defined in your project.
To correct this error
Ensure that the code element that you entered is an existing interface.
If the code element that you entered is defined outside your project, ensure that you have included the correct references in Solution Explorer.
See Also
Concepts
Working with Visual C++ Code in Class Designer