from zentara:
-> Now you may not see the usefulness of the entryconfigure or the cget,
-> but what if you had a more complex menu, and needed to dynamically
-> grey out items?
That is exactly what i did (the cascading menus are a recursive tree,
with several hundred+ total entries dynamically generated). I want
some entries grayed out when some operation is/has been performed and
also to completely disappear (and appear) for other reasons. To do
this i simply included all the:
-> my $menu = $menubar->cascade(-label => '~File');
-> $menu->command(-label => '~New');
-> $menu->command(-label => '~Open');
inside a subroutine ("scanmenus"), run once initially and then called
with:
$mw->bind("<Mouse or Key>"=>sub{scanmenus();$menu->Popup;});
A $mw->Button will also work.
That way, rather than having to use cget and reconfiguring an existing
menu, the menu is generated anew every time it pops up (a menubar would
be harder; you will have to dynamically "destroy" widgets). Since every
instance is just the same as the original (only different) there is no
need for additional entryconfigure code. It also means the initial
state is not a preformatted default, and deals with:
-> I still havn't figured out how to grey out
-> an arbitrary item in a deeply cascaded menu.
because you would also then need to track the index numbers of these
arbitrary items for "entryconfigure" (even more code). Forget
entryconfigure; instead, just include a possible -state=>disabled in
the "command", governed by a conditional expression in the
menu-generating subroutine:
} elsif ( $Ldata !~ /$this1/ ) {
$MM{$this1} =
$MM{$this}->command(-label=>"$this1",-command=>[\&dosub, "$this1"]);
} elsif ( $Ldata =~ /$this1/ ) {
$MM{$this1} =
$MM{$this}->command(-label=>"$this1",-state=>'disabled');
Note that widget names can be elements of a hash (%MM, the main menu;
$this would be a cascade submenu, $this1 an entry). Perl creates the
cascaded menu tree (again, hundreds of total entries) instantaneously.
You would have to include your own "my's" (i never "use strict" because
i am convinced that declaring a variable LOCALLY should be the
exception, not the rule, instead of vice versa w/ strict). But it will
still be the same thing...
thanks, b/t/w for the Ternary operator and the "& 1" test
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