Tk Listbox problem

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

I have a listbox setup like so...

    #Create the tape removal dialog box
    my $remove_dialog = $win->DialogBox(-title=>'Choose a tape',
                                        -buttons=>["Remove", "Cancel"]
+);
    
    #Create the listbox to hold the tape numbers
    my $remove_list = $remove_dialog->Listbox(-width=>'25', 
                                              -height=>'5', 
                                              -font=>$font)->pack;
    #Get the tapes that are stored
    my @stored_tapes = getTapes();
    
    #Put each tape in the listbox
    foreach my $tape (@stored_tapes)
    {$remove_list->insert('end',$tape);}
        
    #Show the $remove_dialog box to the user
    my $remove_result = $remove_dialog->Show;


    if($remove_result eq "Remove")
    {
        my $test = $remove_list->get('active');
        print $test;
    }
[download]

This works fine. The problem is ... when I click Remove with nothing selected in the box
$remove_list->get('active')
defaults to the first value in the list. I would like to be able to check for the case of the user not selecting an option.

Does anyone know how this is possible?

Thanks for any help, Gry

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Re: Tk Listbox problem by jsprat (Curate) on Jul 21, 2003 at 17:52 UTC
Check the return of `$remove_list->curselection`. curselection returns the number of items selected or an empty string for no selection. `perldoc Tk::Listbox` has more information. HTH...	[reply] [d/l] [select]
Re: Tk Listbox problem by bobn (Chaplain) on Jul 21, 2003 at 17:32 UTC
From `perldoc Tk::Listbox`, I can only come up with: `foreach my $tape (@stored_tapes, '<NONE>') {$remove_list->insert('end',$tape);} $remove_list->activate('end'); #Show the $remove_dialog box to the user my $remove_result = $remove_dialog->Show;` [download] In the absence of selection, returns '<NONE>'. You might want to set -selectmode' to multiple or extended to allow more than one selection at a time. --Bob Niederman, http://bob-n.com	[reply] [d/l]
Re: Re: Tk Listbox problem by Grygonos (Chaplain) on Jul 21, 2003 at 17:58 UTC
clarification of my previous post.. I want the script to throw an error or prompt for proper input when a user fails to make a selection in the listbox. Edit: Thanks for the curselection tidbit. Does anyone know of a better way of reading perldoc on win32... dos shell blows.	[reply]
Re: Re: Re: Tk Listbox problem by bobn (Chaplain) on Jul 21, 2003 at 19:11 UTC
If Show returns `'<NONE>'` prompt the user again, thought the curselection() method noted below does look a bit more elegant. Also, on my winNT AS 5.6.1 system, perldoc works, if I recall (don't have it here right now). In any event, there shpould be a an item in Start->Programs for ActiveState Perl Documentation, or somethng to that effect. --Bob Niederman, http://bob-n.com	[reply] [d/l]
Re: Re: Re: Tk Listbox problem by Anonymous Monk on Jul 21, 2003 at 18:04 UTC
Take a look at cygwin	[reply]
Re: Re: Re: Tk Listbox problem by jsprat (Curate) on Jul 21, 2003 at 18:14 UTC
Tk is a standard module with ActiveState, and AS ships HTML docs. Mine is here: D:/Perl/html/site/lib/Tk/Listbox.html. If you're online, try perldoc.com That being said, I installed less for windows, changed the background color of my command prompt. Except for the OLE object browser, I don't use the HTML docs any more.	[reply]