| Allegro CL version 8.2 Moderate update since 8.2 release. 8.1 version |
Arguments: standard-object
Returns the value of the range property of a dialog-item, which indicates the set of valid values from which the end user may interactively choose. The setf of this function may be used to replace the range of a dialog-item, at which time the dialog-item will be redrawn automatically if needed to display the new range.
A variety of dialog-items (widgets) have a range property, though the
meaning varies depending on the type of widget. Among them are
single-item-list
,
multi-item-list
,
and combo-box
. More specific
information may be found on the documentation pages for each widget
class.
Most widgets that use a range use one of two basic types:
multi-item-list
, single-item-list
,
outline
, and
dropping-outline
,
for example, use this type of range.
vertical-scroll-bar
, horizontal-scroll-bar
,
and trackbar
widgets are among those that use this type of range.
When the range is a list of discreet choices, some widget classes use
a list of arbitrary objects that can serve directly as the value of
the widget, while other widget classes use a list of more specialized
objects that encapsulate the values. The classes single-item-list
, multi-item-list
, and
combo-box
are
of the first type. On the other hand, an outline
uses a range where each
member is an outline-item
object, a list-view
's range
contains list-view-item
s, a multi-picture-button
's
range contains button-info
s, a tab-control
's range
contains tab-info
s, and a header-control
's range
contains header-info
s.
When a range contains specialized objects, then the values of these
objects are used for the value of the widget itself, rather than using
the range members directly for the widget value. For example, while a
single-item-list
range would simply
be the list of symbols (:one :two :three)
to allow
the value of the widget to be one of those three symbols, an outline
whose value
may be one of those symbols would have a range whose members are
outline-item
s,
where the value of each outline-item
is one of the symbols.
Sometimes the value of a widget that has a range is a single range
value, and sometimes it is a list of zero or more range values. For
most widget classes this depends on the class; for example, the value
of a single-item-list
or tab-control
is always
either a single value from the range or else nil
if no choices are selected, while the value of a
multi-item-list
, list-view
, or multi-picture-button
is always a list of zero or more range values. For an outline
, on the
other hand, whether the value is a list depends on whether the multiple-selections
property of the widget is turned on.
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 Moderate update since 8.2 release. 8.1 version |