Entry Widget - Perl/Tk

[doni]

Hi,

I am trying to do some error checking on my Entry Widget in this Perl/
Tk test program. I would like to check if the user has entered some
text under Filename before he starts pressing the "Load" button. Will
"validate command" option under Entry Widget work for this. Can anyone
point me how should I go about this.

Here is the source code.
#!/usr/bin/perl

use Tk;

$mw = MainWindow->new;
$mw->configure(-title=>'Test',
-background=>'blue',
-width=>"700",
-height=>"500");

$info = "Start Loading Filename...";

# Create necessary widgets
$f = $mw->Frame->pack(-side => 'top',
-fill => 'x');
$f->Label(-text => "Filename:")->pack(-side => 'left',
-anchor =>
'center');
$f->Entry(-textvariable => \$filename)->pack(-side => 'left',
-
anchor => 'w',
-fill
=> 'x',
-
expand => 1);
$f->Button(-text => "Exit",
-activebackground => "red",
-underline => 1,
-command => sub {exit;})->pack(-side => 'right');
$f->Button(-text=>"Clear",
-command=> sub {$t->delete("0.0",'end')})->pack(-
side=>'right',

-anchor=>'s');
$f->Button(-text => "Save",
-command => \&save_file)->pack(-side => 'right',
-
anchor => 'e');
$f->Button(-text => "Load",
-command => \&load_file)->pack(-side => 'right',
-
anchor => 'e');
$mw->Label(-textvariable => \$info,
-relief => 'ridge')->pack(-side => 'bottom',
-fill => 'x');
$t = $mw->Scrolled("Text")->pack(-side => 'bottom',
-fill => 'both',
-expand => 1);
MainLoop;

# load_file checks to see what the filename is and loads it if
possible
sub load_file {
$info = "Loading file '$filename'...";
$t->delete("1.0", "end");
if (!open(FH, "/$filename")) {
$t->insert("end", "ERROR: Could not open $filename\n");
return;
}
while (<FH>) { $t->insert("end", $_); }
close (FH);
$info = "File '$filename' loaded";
}

# save_file saves the file using the filename in the Entry box.
sub save_file {
$info = "Saving '$filename'";
open (FH, ">$filename");
print FH $t->get("1.0", "end");
$info = "Saved.";
}

Thanks,
doni

 

[Matthew Mundy]

I do not know if validate would work. My solution was to have the
button disabled until the "<<Modified>>" virtual event, then change
its state to active.

Hope that helps. There might be a better way. I am at best an
experienced novice.

 

[doni]

Well, here there may well be people able to help you on Tk, but as I
wrote in my other post to you (well, maybe you didn't receive it) you
may want to check comp.lang.perl.tk!

Michele
--

thanks, I got the answer to my solution from comp.lang.perl.tk.
I posted the same question earlier in comp.lang.perl.tk as well. I
dont know if I am not supposed to do like that. Let me know if I am
not supposed to post the same question in 2 groups.

Thanks,
doni

 

[doni]

You're supposed not to. If there's a *really* good reson to do so,
then you'd better crosspost rather than multipost, i.e. include both
groups in the Newsgroups header. So people from both will know the
answers you received and this will avoid duplicate efforts. If you
find that many people sets Followup-to one group only, then you
probably shouldn't have crossposted in the first place.

Michele

thanks for letting me know.

doni