Using inheritance to build user objects
When you build a user object that inherits its definition
(properties, events, functions, structures, variables, controls,
and scripts) from an existing user object, you save coding time.
All you must do is modify the inherited definition to meet the requirements
of the current application.
For example, suppose your application has a user object u_file_view that
has three CommandButtons:
-
List—displays
a list of files in a list -
Open—opens the selected file and displays
the file in a MultiLineEdit control -
Close—displays a message box and then closes
the window
If you want to build another user object that is exactly like
the existing u_file_view except
that it has a fourth CommandButton, you can use inheritance to build
the new user object, and then all you need to do is add the fourth CommandButton.
To use inheritance to build a descendent user
object:
-
Click the Inherit button in the PowerBar,
or select File>Inherit from the menu bar. -
In the Inherit From Object dialog box, select
User Objects from the Objects of Type drop-down list. -
Select the target as well as the library or libraries
you want to look in.
Displaying user objects from many libraries
To find a user object more easily, you can select more than
one library in the Libraries list. Use Ctrl+click to toggle
selected libraries and Shift+click to select a range. -
Select the user object you want to use to create
the descendant, and click OK.The
selected object displays in the User Object painter and the title
bar indicates that the object is a descendant. -
Make any changes you want to the user object.
-
Save the user object with a new name.