| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
A grid-row
that is an instance of this class allows the user to select and/or
move grid-column
s by clicking the cells
where they cross the grid-row
. The selectable property of a column
must also be true before the column may be interactively selected, and
the movable
property of a column must also be true before the column may be
interactively moved. In other words, a column may be interactively
selected at a particular cell if the column is a selectable one and the row at that
cell is an instance of column-selecting-row-mixin
; and
(likewise) a column may be interactively moved (among the columns in
its grid-column-section
) at a particular
cell if the column is a movable one and the row at that
cell is an instance of column-selecting-row-mixin
.
This feature is typically used only in a grid-row
that serves as a set of
column headers, so that the special column-selecting and/or -moving
behavior does not override other cell-click behavior in the body of
the grid-widget
. Nevertheless, it may
sometimes be desirable to use this class for multiple rows of a grid.
The user uses this feature by moving the mouse cursor into a cell in a
selectable or
movable
grid-column
where it crosses a
column-selecting-row-mixin
row.
The user may click and drag horizontally in this cell to reposition
the grid-column
, or click and release
without moving the mouse more than *start-drag-slack*
pixels to toggle
the selected
property of the column. When the mouse button is released after a
drag, the column is positioned among the columns in its grid-column-section
so that
it is just to the right of all of the columns whose vertical centers
are to the left of the final vertical center of the drag box (this
should be intuitive). A drag may be canceled either by pressing the
Escape key before releasing the mouse button or by releasing the mouse
button while the drag box is positioned where the column would snap
back to where it was already.
An individual selectable grid-column
may be added to the
current set of selected columns in its grid-column-section
by holding down the
control key while clicking the column; if the column is already
selected, then this deselects the column instead. If the shift key is
held down while clicking a selectable column, then the range
of columns that just encompasses all of the columns that were already
selected plus the column that was clicked are then left in a selected
state (regardless of their selected state beforehand).
This class must be mixed with grid-row
(or one of its subclasses)
to make an instantiable class. It is best to specify such mixin
classes ahead of the grid-row
class in the list of
superclasses for a new class, so that the small amount of special
behavior from the mixin class will override the more general behavior
of the grid-row
class. For example:
(defclass my-column-selecting-row (column-selecting-row-mixin grid-row)())
The above default mouse click behavior may be overridden by custom cell-click methods.
For an example of column-selecting-row-mixin, see the Navigator dialog
example (on the Examples tab) entitled "Grid-Widget: a basic
replicated editable-text column". See also the class column-header-row
, which
combines this class with column-sizing-row-mixin
and grid-row
for use as a
typical row of column headers.
See also slide-subsection.
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 |