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TiedListbox(3)	      User Contributed Perl Documentation	TiedListbox(3)

NAME
       Tk::TiedListbox - gang together Listboxes

SYNOPSIS
	   use Tk::TiedListbox

	   $l1 = $widget->Listbox(-exportselection => 0,...);
	   $l2 = $widget->Listbox(-exportselection => 0,...);
	   $l3 = $widget->Listbox(-exportselection => 0,...);
	   $l1->tie([$l2,$l3]);

DESCRIPTION
       TiedListbox causes two or more Listboxes	to be operated in tandem.  One
       application is emulating	multi-column listboxes.	The scrolling,
       selection, or both mechanisms may be tied together. The methods tie and
       untie are provided, along with overridden versions of some of the
       Listbox methods to provide tandem operation.

       Scrollbars are fully supported. You can use either explicitly created
       Scrollbars, the ScrlListbox widget, or the Scrolled super-widget.
       Tricks to "attach" multiple tied	listboxes to a single scrollbar	are
       unnecessary and will lead to multiple calls of the listbox methods (a
       bad thing).

       The configuration options, geometry, and	items of the Listboxes are not
       altered by tying	them. The programmer will have to make sure that the
       setup of	the Listboxes make sense together. Here	are some (unenforced)
       guidelines:

       For listboxes with tied selection:

       o   set -exportselection	to 0 for all but possibly one Listbox

       o   use identical -selectmode for all Listboxes

       o   if items are	added/deleted, they should be done all at once and at
	   the same index, or the selection should be cleared

       o   Listboxes should have the same number of items

       For listboxes with tied scrolling:

       o   use the same	window height and font for all Listboxes

       o   Listboxes should have the same number of items

METHODS
       $listbox->tie?(?option?,	[listbox,...])?
	   Ties	together $listbox and the list of Listboxes with the given
	   option. Returns $listbox.

	   If no arguments are given, returns a	list containing	two items: the
	   tie option ("scroll", "selection", or "all")	and the	list of
	   Listboxes to	which $listbox is tied.

	   option can be one of	"scroll", "selection", or "all".  If omitted,
	   "all" is assumed. "scroll" makes the	tied Listboxes scroll
	   together, "selection" makes selections occur	simultaneously in all
	   tied	Listboxes, and "all" effects both actions.

	   All the Listboxes are untied	(if previously tied) before being tied
	   to each other; hence	a Listbox can only be in one "tie group" at a
	   time. "Tiedness" is commutative.

	   The tie method can be called	with either Listbox or TiedListbox
	   objects. All	Listbox	objects	specified are reblessed	to TiedListbox
	   objects.

	   Code	such as	below can be used to tie ScrlListboxes:

	       $slb1=ScrlListbox(...); # or Scrolled('Listbox',...
	       $slb2=ScrlListbox(...); # or Scrolled('Listbox',...
	       $slb1->tie([$slb2->Subwidget('scrolled')]);

       $listbox->untie()
	   This	function unties	the Listbox from its "tie group". The other
	   items in the	"tie group" (if	more than one) remain tied to each
	   other.

	   Returns a list containing two items:	the old	tie option ("scroll",
	   "selection",	or "all") and the list of Listboxes to which $listbox
	   was tied.

OVERRIDDEN METHODS
       You probably don't care about these. They are just details to tie
       together	the behaviors of the listboxes.

       All overriden methods take identical arguments as the corresponding
       Listbox methods (see Tk::Listbox	for a full description). All
       overridden methods that take an index interpret that index in the
       context of the listbox object provided.

       $listbox->activate(...)
       $listbox->selection(...)
	   To allow tied selection, these functions are	overridden for
	   listboxes tied together with	the "selection"	or "all" option. When
	   an item is selected or activated in one listbox, the	items with the
	   same	index (if present) are selected	or activated in	all tied
	   listboxes.

	   The selection('includes',...) submethod returns only	information
	   about the given $listbox.

       $listbox->scan(...)
       $listbox->see(...)
       $listbox->yview(...)
	   To allow tied scrolling, these functions are	overridden for
	   listboxes tied together with	the "scroll" or	"all" option. When one
	   listbox is scrolled,	all the	other tied listboxes are scrolled by
	   the same number of items (if	possible). An attempt is made to keep
	   items of the	same index at the top of each tied listbox, while not
	   interfering with the	normal scrolling operations.

	   The yview method with no arguments returns only information about
	   the given $listbox.

	   Horizontal scrolling	(via xview) is not tied.

BUGS
       Reblessing the widgets to TiedListbox might be too weird. It will
       disable any additional features for widgets in a	class derived from
       Listbox (none yet that I	know of).

       The bindtags for	reblessed widgets aren't updated. This is probably
       wouldn't	be a good thing	to do automatically anyway.

AUTHOR
       Andrew Allen <ada@fc.hp.com>

       This code may be	distributed under the same conditions as Perl.

perl v5.32.1			  1998-09-21			TiedListbox(3)

NAME | SYNOPSIS | DESCRIPTION | METHODS | OVERRIDDEN METHODS | BUGS | AUTHOR

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