Simple and gloriously concise example (as opposed to mine!). Here, whether the classes are native, or whether they are concrete instead of interfaces won't change the need for a cast; all the involved objects have commonalities but also important differences, and you want to treat them differently. Refactoring (if it were possible) to support "proper" polymorphism would obviously a bad idea, at least for me.
Cheers Juan Pablo Califano 2010/6/8 Henrik Andersson <[email protected]> > Juan Pablo Califano wrote: > >> I agree with you, but I'add for the sake of completeness that, sometimes, >> relaxing the rules a bit becomes a necessary evil, like for instance, when >> doing a cast. >> >> > I have another example of where a typecast can be useful. When you really > do need only BaseClass, but want to add some processing, if and only if, the > object is of a specific DerivedClass. > > An examples of this example would be a display list crawler. You are just > outputting all the objects, you need nothing other than DisplayObject for > that. However, you want to go deep, so you use the "as" operator to get a > reference to a DisplayObjectContainer. If it succeeds, you recurse. If not, > not a problem. > > _______________________________________________ > Flashcoders mailing list > [email protected] > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
