Download user manual - Instant Developer Documentation

Andrea Maioli – Instant Developer: User's Guide
5.10.2 Virtual methods
An extended document is for all intents and purposes a normal document, with the difference that it inherits the properties, collections, and behaviors (methods and events)
of all its base documents. So, you can use an extended document in all the possible
ways and contexts covered up to now.
Extended documents behave according to the rules of object orientation, to which
you can refer for more information. You can therefore create virtual methods that specialize the behavior of an extended object and that are resolved directly at runtime.
Instant Developer recognizes the presence of virtual methods from the fact that a
derived class contains a procedure or non-private function with the same name as that
contained in its base class. The easiest way to specialize a method in a derived class is
to drag & drop the method from the base class onto the derived class while holding
down ctrl+shift. This copies the method to the derived class, including the parameters
and the body. After copying, you can modify the code, deleting or replacing that copied
from the base method.
Procedure for specializing a virtual method in a derived class
Within a method of a derived class, you can call methods of the base class by typing its
name and selecting the token that begins with base instead of this. Only within an event
can you call the base event.
How to call the base method from an overriding method
244