> I have two questions about interface usage. > > 1. How interfaces are to handle when casting? > Theoretically it should be safe to do this: > > TObservable = class > public > procedure Register( obsv: IObserver ); > private > procedure NotifyObservers(param: TParameter); > fObservers: TFPObjectList; > end; > > procedure TObservable.Register( obsv: IObserver ); > begin > fObservers.add(TObject(obsv)); > end;
No it is not safe. The interface points to an interface table, and you cast it if it were a class VMT. Have a look at IInterfaceComponentReference and use/implement the getcomponent method. Note that this was added post-2.2.0 _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
