From: Vince Morgan on 15 Feb 2006 01:02
"Ulrich Eckhardt" <doomster(a)knuut.de> wrote in message
> > Although most calls are objects of the base type, there are others of
> > derived type.
> > So as you can see above I have cast the base type objects to the derived
> > type in the callback. (correct cast?).
> > This is working fine, but I have come to realize I hadn't planned for
> > this, and that there may be a more appropriate method that deals with
> > possible future changes such as additional parent classes.
> This should be almost fine. You don't tell us about it, but On_Callback()
> is probably a virtual function defined in the baseclass. So, there is no
> need to cast to HoverTextButton, casting to the baseclass HoverButton
> should be enough, while the virtual dispatch does the rest.
I've slightly restructured the classes to use virtual dispatch, and it's
Thank you again Uli
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