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QUESTION:
I am trying to intercept procedure Mouse_Down for all classes, so I am trying to intercept it at the cUIObject level (which is defined in the Visual DataFlex runtime C code):
Procedure Mouse_Down For cUIObject Integer iWindow Integer iPosition
Forward Send Mouse_Down iWindow iPosition
Set PiMyProperty To 0
End_Procedure
ANSWER:
The use of "for class" is discouraged. The "for class" replaces the method at the named class level. So, in the case of cUIObject, you are replacing mouse_down. There is no way you can forward this because there is nowhere to forward this to. The forward would go to cObject, where it is not defined.
The reason we don't recommend this is that:
1) You are changing our class - a class you do not control
2) You are changing runtime C behavior - behavior you cannot see
3) Changing messages defined in C does not work as expected (as it would in DataFlex code)
We use this technique in a couple of places internally because we understand the side effects and we can see the C code.
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