| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
Arguments: check-box
Determines whether :gray
is a third meaningful
value for the
argument check-box, which should be a check-box
instance.
The default value is nil
, in which case the
check-box will be blank when its value is nil
and otherwise will show a check mark. Clicking
on the check-box will toggle its value between nil
and t
(unchecked and
checked). Other equivalent action such as selecting and pressing the
Space bar will also toggle between checked and unchecked.
If this method returns a non-nil
value other
than the value :except-interactively
, then the
check-box will show a third grayed-out state when
its value is
:gray
. This intermediate state is typically used
either to indicate that a true-or-false value is unknown or
undetermined, or that some but not all of a set of subchoices are
selected. Clicking on the check-box will cycle
its value between nil
, t
, and :gray
(in that order).
If the value returned by the method is the keyword
:except-interactively
, then the check-box's value
may be set to :gray
programmatically by calling
(setf
value), but interactive gestures (clicking the check-box or
pressing the spacebar when it has the keyboard focus) will only toggle
the value between t
and nil
. If the value is :gray
,
clicking will change it to t
(checked) and
then toggle between t
and nil
. (This value may be useful when you want the gray
state before any user action on the check box at all, but once the
user acts, the only choices are checked and unchecked.)
This property cannot be changed on an existing check-box
(except in the inspector
for a check-box on a form designing a dialog). The only way to specify
the value programmatically is to pass the :three-state argument when
calling make-instance to
create the check-box.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |