Hello,

I want to validate the input of an entry widget. Only positive hexadecimal digits shall be allowed.

Here my code:

#!/usr/bin/perl

use strict;
use warnings;

use Tk;

use Data::Dumper;


my $mw = new MainWindow;
$mw->title ("Perl/Tk - Entry Valdiation");

my $entry1 = $mw->Entry ( '-width'           => 30,
                          '-validate'        => 'key',
                          '-validatecommand' =>
                          sub
                          {
                              print Dumper( \@_ );                    
+          
                                                           
                              return 0 unless( $_[0] =~ m/^[0-9a-fA-F]
++/ )
                          } );

$entry1->pack();

MainLoop;
[download]

After the input of a valid character I can never remove it again. The first character is always there then. In the dumped output I can see that the character should be gone, but it is still visible in the entry.

Am I doing something wrong? Is it a bug?

Thanks alot for your help.

Greetings,

Dirk