>>If I want to change any of them, I need to subclass first, in order to avoid app-specific changes becoming a part of every project I develop. Or worse yet, if I don't create my own subclass, my changes will disappear when Microsoft updates the foundation classes.
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>Actually, if I remember correctly, an article in FoxPro Advisor discussed this aspect of using the FFC.
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>I belive the recomendation was to subclass all the base classes, then modifiy all of the FFC classes in _BASE to subclass from your own base classes.
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>This way, you can add or modify functionality of the subclassed base classes in the layer you put between VFP and _base. Other than that you can subclass the _FFC classes.
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>What this gives you is a way to modify and extend the _FFC and when it is upgraded, all you have to do is redefine the classes in _BASE again. If my memory serves, there was even code for a utility that did the reassignment for you too.
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>I think it is also necessary to modify the wizard to use your subclasses of the _FFC in the ap builder.
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>BOb
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>PS: I also know that on the MSDN web page, there is also an article on extending the _FFC by a member of the fox team.

I'd still opt for Joel's direction - subclass everything from _ffc, and then subclass once more from that layer into the app's directory. The reason for this is that we're getting three layers - the _ffc layer remains untouched; the middle layer inherits from _ffc and can be modified on an enterprise basis, and all the app level classes inherit from the middle layer and go into their own specifics. This way, there are a very few things to do if _ffc layer changes, maybe just adjust some things somewhere in the middle layer. Of course, someone should create an utility for this, or even better, hack the app builder to do it - create middle layer if it isn't there, and create empty subclasses off the middle layer for each new app.