Hi Kamal!



>Hi Dragan,
>
>>What's the difference, in this case? The forms should be (instances or subclassed instances) of the same class, so they could have the same EditState_assign routine, right? So, the code handling this event is stored only once; therefore having an Observer is almost superfluous, _unless_ it's doing some other things too.
>
>You are right. Both the methods are going to work. Though, what by having another object which overlooks is more flexible because, I can then register just my second page and it would work without any problems. Moreover, it would be more easy to reuse it for e.g. use in another project which uses a different framework for developement.
>

The fly in the ointment on these types of constructs is the Private datasession. This is one of the reasons (amongst many) that I try to encapsultate behavior and state changes within the affected object. VFP is still squirrelly when it comes to dataenvironments (and other things). IE, that earlier thread on not having a Controls collection in the DE.

The book you recommended *is* an outstanding book on the whole theory.

Not to criticize VFP, but there are a lot of theoretical OOAD and OOP concepts that I'd love to employ but get shot down by either lack of internals support or poor performance. This is one of the reasons why I back off of mediators and the like. If I can't wholly implement them without compromises, I don't want to deal with them.