If you only allow the user to enter a single digit number, then change your code to:

use strict;
use Tk;


my $page2;
my $w=0;  
my $wtf; 
my $wentry= 3; 
my $wcb;

$page2 = MainWindow -> new();
$wcb = $page2 ->Checkbutton (-text=> '/W:', -variable=> \$w, -font=>"A
+dobe 10")->pack;
#$wcb->select();
$wtf = $page2 ->Entry (-textvariable=> \ $wentry, -width=>8,
            -validate=> 'key', 
            -validatecommand=> sub{$_[0] =~ /^\d{0,1}$/},
            -invalidcommand=> sub{$page2->bell}
)->pack;
MainLoop;

[download]

You have to allow blank, otherwise the user cannot clear the entry before entering.

If you allow multi-digit numbers, change the regexp to ^\d*$.

In reply to Re: Entry widget, default value and validatecommand by pg
in thread Entry widget, default value and validatecommand by Real Perl

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