1Menu::Item(3)         User Contributed Perl Documentation        Menu::Item(3)
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NAME

6       Tk::Menu::Item - Base class for Menu items
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SYNOPSIS

9          require Tk::Menu::Item;
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11          my $but = $menu->Button(...);
12          $but->configure(...);
13          my $what = $but->cget();
14
15          package Whatever;
16          require Tk::Menu::Item;
17          @ISA = qw(Tk::Menu::Item);
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19          sub PreInit
20          {
21           my ($class,$menu,$info) = @_;
22           $info->{'-xxxxx'} = ...
23           my $y = delete $info->{'-yyyy'};
24          }
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DESCRIPTION

27       Tk::Menu::Item is the base class from which Tk::Menu::Button,
28       Tk::Menu::Cascade, Tk::Menu::Radiobutton and Tk::Menu::Checkbutton are
29       derived.  There is also a Tk::Menu::Separator.
30
31       Constructors are declared so that $menu->Button(...) etc. do what you
32       would expect.
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34       The "-label" option is pre-processed allowing ~ to be prefixed to the
35       character to derive a "-underline" value. Thus
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37           $menu->Button(-label => 'Goto ~Home',...)
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39           is equivalent to
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41           $menu->Button(-label => 'Goto Home', -underline => 6, ...)
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43       The "Cascade" menu item creates a sub-menu and accepts these options:
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45       -menuitems
46           A list of items for the sub-menu.  Within this list (which is also
47           accepted by Menu and Menubutton) the first two elements of each
48           item should be the "constructor" name and the label:
49
50               -menuitems => [
51                              [Button      => '~Quit', -command => [destroy => $mw]],
52                              [Checkbutton => '~Oil',  -variable => \$oil],
53                             ]
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55       -postcommand
56           A callback to be invoked before posting the menu.
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58       -tearoff
59           Specifies whether sub-menu can be torn-off or not.
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61       -menuvar
62           Scalar reference that will be set to the newly-created sub-menu.
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64       The returned object is currently a blessed reference to an array of two
65       items: the containing Menu and the 'label'.  Methods "configure" and
66       "cget" are mapped onto underlying "entryconfigure" and "entrycget".
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68       The main purpose of the OO interface is to allow derived item classes
69       to be defined which pre-set the options used to create a more basic
70       item.
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BUGS

73       This OO interface is very new. Using the label as the "key" is a
74       problem for separaror items which don't have one. The alternative would
75       be to use an index into the menu but that is a problem if items are
76       deleted (or inserted other than at the end).
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78       There should probably be a PostInit entry point too, or a more widget
79       like defered 'configure'.
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83perl v5.30.1                      2020-01-30                     Menu::Item(3)
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