The class of all control windows that are implemented in the operating
system (the related lisp-widget-window class is for
controls implemented in Lisp). An application can usually use the
various instantiable dialog-item classes (also called controls or
widgets) without concerning itself with their associated widget-window
or lisp-widget-window classes which are internally instantiated to
create the actual windows that appear on the screen for the logical
dialog-items created by the application.
But if an application needs to intercept low-level window events that are not exported as one or more of the dialog-item's event-handler properties, then the application should make subclasses of both the dialog-item class and the associated widget-window or lisp-widget-window class, and then add the needed methods that specialize on the window subclass, such as virtual-key-down or mouse-left-down methods. A widget-device method also should be added to associate the window class with the dialog-item class.
In addition, to receive low-level window events for widget-windows (which are implemented in the operating system) but not for lisp-widget-windows (which are implemented in lisp), the function subclass-widget must be called on the widget-window after it has been created by adding a dialog-item to a parent window. Note that this function has nothing to do with CLOS classes, but instead performs what Microsoft calls "subclassing" to intercept low-level window events that are normally handled within the operating system by the control's own window procedure there.
Common Graphics and IDE documentation is described in About Common Graphics and IDE documentation in cgide.htm.
The documentation is described in introduction.htm and the index is in index.htm.
Copyright (c) 1998-2000, Franz Inc. Berkeley, CA., USA. All rights reserved.
Created 2000.10.5.