6.3.2 Virtual methods

Classes have virtual methods, just as objects do. There is however a dierence between the two. For objects, it is sucient to redeclare the same method in a descendent object with the keyword virtual to override it. For classes, the situation is dierent: virtual methods must be overridden with the override keyword. Failing to do so, will start a new batch of virtual methods, hiding the previous one. The Inherited keyword will not jump to the inherited method, if virtual was used.

The following code is wrong:

The compiler will produce a warning:

The compiler will compile it, but using Inherited can produce strange eects.

The correct declaration is as follows:

This will compile and run without warnings or errors.

If the virtual method should really be replaced with a method with the same name, then the reintroduce keyword can be used:

This new method is no longer virtual.