>>>Hi Peter,
>>>
>>>abstract classes are necessary to define the pure interface for your concrete classes. This way you can react to language- and property modifications. From VFP9 point of view this might not be necessary anymore, as there won't be any changes coming by MS, but for me that's no reason to change my behaviour.
>>
>>I can imagine that at least one child from a base class is 'necessary' or at least useful. But if that child contains ALL that you need in a part of the application (apart from what must be set in the instance itself) then why declare it abstract?
>>
>
>i.e. before VFP had the anchor-property we had created this property within out framework by default. With VFP introduction to this, we ran into an error as there was already a property called 'anchor' within VFPs baseclass.
>So all we had to do, was renaming our property and changing the corresponding code snipets.

But this is not a problem that can only be solved in an abstract class. And it can also occur in a concrete class. Adding properties and methods is also done in conctrete classes.