>Paul,
>
>>I'd probably need/want something like this for the cContrls library, an I-Layer class that cForms::cBaseForm inherits from (instead of a base form), plus a few of the kCustCtl classes.
>
>How do you see this working for backward compatibility with existing projects that don't currently have an I-Layer?
>
>Regards,

You should just be able to add the new I-Layer classes to your existing projects and recompile. Instead of the framework inheriting from VFP's base classes, it would inherit from this new I-Layer class (which inherits from the VFP base class). By default, there isn't going to be any code in these I-Layer classes so there shouldn't be any problems with breaking apps. by a change in method signatures. It would, however, require some changes in the framework code for any code that is in the existing VFP methods/events.

Eg.

IF !DODEFAULT()
   RETURN .F.   && Or whatever value was previously being returned (like a numeric instead).
ENDIF

* Existing framework code here

It would then be up to the developer to make sure any code they add to the I-Layer doesn't break the framework.