Generic FunctionPackage: cgToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 9.0
Unrevised from 8.2 to 9.0.
8.2 version

subclass-widget

Arguments: dialog-item

Use of this function is deprecated. Common Graphics now always internally calls this function on all Microsoft widgets, and so there is never a need for an application to call it. Calling this function will now simply do nothing.

Performs what might be called "MS subclassing" on the window of dialog-item. This has nothing to do with CLOS classes, but rather causes lisp to intercept all low-level messages that are sent to widget windows and are normally handled within the Windows operating system where these widgets are implemented. All low-level Windows events for dialog-item will be passed to the pc:control-procedure generic function. In addition, the keypress and mouse-click events will call an event method for the dialog-item's window and that event.

You need to call subclass-widget only if you want to handle these low-level Windows events that are usually handled by MS-Windows internally. For example, when a user types a new value into an (single-line) editable-text widget, you normally know only what the new string and the old string are; if you want to know what actual key was pressed, then you will need to call subclass-widget and then write an event method on the window to handle the keypress event. Or you may want to intercept a mouse click on a widget even when its value is not changed by the click.

If subclass-widget is called on a widget that is already subclassed, no action is taken and nil is returned, otherwise t is returned.


Copyright (c) 1998-2012, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 9.0. This page was not revised from the 8.2 page.
Created 2012.5.30.

ToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 9.0
Unrevised from 8.2 to 9.0.
8.2 version