vr786 has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I want to validate the fields , i am trying like this but i don't know where iam going wrong please , any one can explain....it. 

#!/usr/bin/perl -w
use strict;
use Tk;

my $opt = "0";
my $opt1 = "0";

my $mw = MainWindow->new();
    $mw-> geometry("400x100");
    $mw -> configure(-background => "cyan",
                    -foreground => "lightblue"
);


my ($var, $var1);

 $opt = $mw->Optionmenu(
        -background => "lightgreen",
        -options => [[jan=>1], [feb=>2], [mar=>3], [apr=>4]],
        -variable => \$var,
        -command => \&sub_opt,
       )->pack;
$opt->addOptions([may=>5],[jun=>6],[jul=>7],[aug=>8]);
my $exit_but = $mw->Button(-text=>'Exit',
    -command=>sub{
         print "Var= $var  Var1= $var1\n";
         $mw->destroy},
    -state => 'disabled',
    )->pack(-side=>"bottom");

 $opt1 = $mw->Optionmenu(
        -background => "lightgreen",
        -options => [qw(test1 test2 test3)],
        -variable => \$var1,
        -state => 'disabled',
        -command =>\&sub_opt1,
  )->pack;
     
MainLoop;

sub sub_opt {
                if($var ne " ") {
                        $opt->configure(-state => 'disabled');
                        $opt1->configure(-state => 'normal');
                } else {
                        $opt -> configure(-state => 'disabled');
                        }
}

sub sub_opt1 {
                if ( $var1 ne " ") {
                $opt1->configure(-state => 'disabled');
                $exit_but->configure(-state =>'normal');
                } else {
                        $exit_but->configure(-state => 'disabled');
                }
}

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Re: optionmenu configure problem in perl tk
by biohisham (Priest) on Nov 08, 2010 at 08:30 UTC
    It doesn't seem that Optionmenu objects have support for the configure option. running your code while the lines $opt->configure(...) and $opt1->configure(...) are commented out yields the Tk widget.

    Check Optionmenu Configuration Options...

    Excellence is an Endeavor of Persistence. A Year-Old Monk :D .
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      Tk::Optionmenu is derived from Tk::Menubutton and probably has support for configuring most, if not all, of its options.

      The documentation is somewhat brief and possibly ambiguous in terms of making a clear distinction between options of the widget (e.g. $w->configure($option => $val); and options of the menu (e.g. $w->addOptions([@new_options]);).

      Try this example code:

      #!perl

use 5.12.0;
use warnings;

use Tk;
use Tk::Optionmenu;

my $mw = MainWindow->new();

my $om = $mw->Optionmenu(
    -options => [qw{Zero One Two Three}],
)->pack();

my $state = 0;
my @states = qw{normal disabled};

$mw->Button(-text => q{Toggle State}, -command => sub {
    $state ^= 1;
    $om->configure(-state => $states[$state]);
})->pack();

$mw->Button(-text => q{Exit}, -command => sub { exit })->pack();

MainLoop;

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      -- Ken

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Re: optionmenu configure problem in perl tk
by zentara (Cardinal) on Nov 08, 2010 at 13:24 UTC
    I want to validate the fields

    The only widget I know of in Tk, that supports validation, is the Tk::Entry. Additionally, your program dosn't run as shown, it crashes because of the way you specify your -command callbacks. When you specify 

    -command => \&sub_opt,

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    the command is executed immediately when the Optionmenu is being created, and it will fail with an error. You want to wrap the command in or a sub{} like this: 
    -command => sub { \&sub_opt },

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    When you make callbacks, you set them up to be something that is "called later" not immediately.

    Here's a bit more of an explanation: 

    #!/usr/bin/perl

#for example the following is wrong
my $row = 0;
my $column = 0;

for (my $i = 9; $i >= 0; $i--)
{
$button{$i} = $mw->Button(-text    => "$i",
                         -width   => '3',
                         -height  => '1',
                         -command => &numpress($i))
                  ->grid(-row     => $row,
                         -column  => $column);

$column++;
if($column > 2){$column = 0; $row++;}
}
MainLoop;

#######################################################
# Now the problem is here:

  -command => &numpress($i))

# The thing being assigned to the "-command" attribute needs 
# to be an anonymous subroutine, a reference to a named subroutine, 
# or else a reference to an array whose elements are: 
# named_subroutine_ref, arg1(, arg2 ...) -- in other words, 
# either of the following would be the right way to do what you want:

  -command => sub { numpress( $i ) }

# or

  -command => [ \&numpress, $i ]

#The way you had it written, your subroutine is actually being called 
#when the Button is being created, and Perl/Tk is trying to use the 
#return value of the sub as the value for "-command" -- not good.

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    I'm not really a human, but I play one on earth.
    Old Perl Programmer Haiku ................... flash japh
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