Adding Classes to Your Schema

Although a schema inherits all classes and their associated properties, methods, and constants from its superschemas, these inherited classes are not displayed by default in the Class Browser of the subschema. Instead, for the sake of clarity, only classes local to the schema are displayed, as well as any superschema classes to which subclasses, methods, or constants have been added. For this reason, when you open the Class Browser for a newly defined schema, only the Object class is displayed initially. For example, after using the F4 functionality to add the Window class to the Class Browser (when there are no subclasses of Window in the current view schema), the Window item icon is a leaf.

You must use the F4 search functionality to add additional subclasses of the Window class (for example, the Form class or a Control subclass).

Only classes specifically added using F4 are displayed, unless you specifically add a subclass to the view schema.

You can immediately begin adding subclasses to the Object class and defining properties and methods of those classes. However, if you want to add a subclass, method, property, or constant to some other class that is defined in a superschema, you must first make that superschema class visible in the Class Browser of your new schema or schema view. For more details, see "Controlling the Use of Elements in Other Schemas", in Chapter 1.

To add a subclass to an existing class in a superschema, you may first have to find the class that you want to subclass.