| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
A non-instantiable class that can be mixed with the grid-column
class to
create grid columns whose cells act like check-box
controls. Each cell in
the column will implement the pseudo-control if the row of that cell
is an instance of a grid-row
subclass that mixes in the
widget-row-mixin
class.
To ensure that this mixin class' methods take precedence over other
methods that specialize on grid-column
, this mixin class generally should
appear first in a defclass
expression's list of superclasses, as in:
(defclass my-check-box-column (check-box-column-mixin my-subclass-of-grid-column) ...)
The draw-cell method provided
by this mixin will call read-cell-value to determine whether to draw the
check mark. If read-cell-value
returns nil
, it will not draw a check mark,
and otherwise it will.
When the user clicks the check-box gadget displayed in the cell, the
cell-click method
provided by this mixin calls write-cell-value with a value of
either t
or nil
so
as to change the domain value represented by the cell. Alternately
the user may press the spacebar or the enter key to simulate clicking
the check-box.
The title-reader property of the column should be used to determine the string to display in each check-box cell. The click-must-be-on-gadget property may be used to determine where the user must click within the cell to activate the cell's gadget.
See the section Built-In Grid Cell Widgets on the page for the
grid-widget
class for an
overview of the grid column mixins.
A quicker but less object-oriented alternative to using the widget-column-mixin
classes is to
write cell-widget methods.
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 |