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Perl/Tk Tutorial - Create GUI with Perl's Tk Module
Some Tk Commands

Some Tk Commands

bind
The bind command associates Perl code with events. If you want to do something when the user double-clicks a item in a listbox or when he/she press any button(say F1), bind is what you need. Lets bind something in the next example.

Syntax:
$widget -> bind(<sequence>, Callback);
<sequence> stands for the sequence of button/mouse presses. It should be given in the following pattern...
<modifier-modifier-type-detail> . For example...
<Control-Alt-Key-t> - Control+Alt+T.
Control and Alt are the modifiers and Key is the type with t as the detail. See the next example and you will understand.


#!/usr/local/bin/perl
use Tk;
# Main Window
my $mw = new MainWindow;

my $lab = $mw -> Label(-text=> " The Bind command ",
	-font=>"ansi 12 bold") -> pack;
my $lst = $mw -> Listbox() -> pack;
$lst -> insert('end',"Don't double-click this.");
$lst -> insert('end',"Don't double-click this either.");
$lst -> insert('end',"Don't even think of double-clicking this.");
$lst -> insert('end',"You may double-click this.");
$lst -> insert('end',"No. Negative. Nay. Nope. Get the message?");
#Bind the double click event to the list box
$lst -> bind ('<Double-ButtonPress-1>', sub { double() });

my $all_keys = $mw -> Label(-justify=>"left",
	-text=>"Press any of the following...
Control+A
Control+Shift+A
Control+Alt+T
Right click
Control+Escape") -> pack;

#Exit when the escape key is pressed
$mw -> bind('<Key-Escape>', sub { exit });
#Shows a helping dialog box when F1 is pressed
$mw -> bind('<Key-F1>',sub { help(); });
#Binds misc keys.
$mw -> bind('<Control-Key-a>', sub { 
	$mw -> messageBox(-message=>"You pressed Control+A, did'nt you?")
});#Control+A
$mw -> bind('<Control-Key-A>', sub { 
	$mw -> messageBox(-message => "Control+Shift+A, right?"); 
	});#Control+Shift+A
$mw -> bind('<Control-Alt-Key-t>', sub { 
	$mw -> messageBox(-message => "Control, Alt and T"); 
});#Control+Alt+T
$mw -> bind('<ButtonPress-3>', sub { 
	$mw -> messageBox(-message => "The right way to click."); 
});#Right click
$mw -> bind('<Control-Key-Escape>', sub { 
	$mw -> messageBox(-message => "You must be a married man. 
What you pressed remindes married men of what they never will have
 - Control or Escape.");
});#Control+Escape 

MainLoop;

#The helping function
sub help {
	$mw -> messageBox(-message=>"Did you ask of help?
You ain't getting any.
Ha Ha Ha!");
}

#This happens at double-click
sub double {
	$mw -> messageBox(-message=>"You double clicked something.
This script is simple - so it won't display what you clicked on.
But if you want a sript that is able to do that, 
write to me at binnyva, gmail
and I will send you a better script.");
}
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