Updating values in Tk Toplevel object

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

It's me back again fellow monks!

I got a long way with multiple widows being opened from menues etc. after your advice yesterday.

I have a window with a BrowseEntry object at the top, then a series of LabEntry objects. I can select the entry I want in the BrowseEntry and use DBI to get it form the database, but how do I fill in teh values in teh LabEntry's?

Gotta be something simple that this simple initiate is missing!

Pardon the code, it is at a very early stage! I am just trying to get a grip of this Tk stuff.

sub doTLUser {
    if (! Exists($tlu)) {
        $tlu = $mainwindow->Toplevel();
        $tlu->title("User Management");

        $lb = $tlu->BrowseEntry(-label => 'Username',
            -variable => \$search_string,)->pack;
        $lb->bind("<Return>", \&do_search);
        $lb->focus;
        $SQL = "SELECT username FROM user;";
        $sth = &Do_SQL;

        while ($username = $sth->fetchrow_array) {
            push @listnames, $username;
        }
        $sth->finish;
        $lb->insert('end', @listnames);

        $tlu->LabEntry(-label => "First Name",
            -labelPack => [-side => "left", -anchor => "w"],
            -width => 20,
            -textvariable => \$user->{firstname})->pack(-side => "top"
+,
                -anchor => "ne");

        $tlu->LabEntry(-label => "Last Name",
            -labelPack => [-side => "left", -anchor => "w"],
            -width => 20,
            -textvariable => \$user->{lastname})->pack(-side => "top",
                -anchor => "ne");

        $tlu->LabEntry(-label => "Password",
            -labelPack => [-side => "left", -anchor => "w"],
            -width => 20,
            -textvariable => \$user->{password})->pack(-side => "top",
                -anchor => "ne");


        $tlu->Button(-text => "Close",
            -command => sub {$tlu->withdraw})->pack(-side => "bottom")
+;
    } else {
        $tlu->deiconify();
        $tlu->raise();
    }
}

#
# do_search
# Take the variable returned by the BrowseEntry and search for it in t
+he database.
#
sub do_search {
    print "String returned: $search_string\n";
    $SQL  = "SELECT username, firstname, lastname, password FROM user 
+WHERE username =\'$search_string\'";
    $sth = &Do_SQL;
    while ($user = $sth->fetchrow_hashref) {
        print "$user->{firstname}\n";
        return;
    }
    print "User not found so enter data\n";
    return;
}
[download]

Comment on Updating values in Tk Toplevel object Download Code

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Re: Updating values in Tk Toplevel object by bobn (Chaplain) on Jul 17, 2003 at 22:06 UTC
UPDATE: If code you posted doesn't work to do the update, I think I see why. When you create the LabEntry, you are setting `-textvariable => \$user->{firstname}`. Then when you retrieve from the database, you are saying: `$user = $sth->fetchrow_hashref` - which overwrites the the hashref $user you used in the LabEntry - if use use `print "$user\n"` before and after the the `fetchrow_hashref`, they should be different. This is the problem, to fix it, preserve $user by fetching to a different hashref, then say `$user->{firstname} = $other->{firstname}`. This stuff is so cool. Having bound a variable to the -textvariable, you just change that variable and it automagically works: `#!/usr/bin/perl -w use Tk; my %User = ( firstname=>'bob' ); my $user = \%User; my $mw = MainWindow->new(); my $lbe = $mw->LabEntry(-label => "First Name", -labelPack => [-side => "left", -anchor => "w"], -width => 20, -textvariable => \$user->{firstname})->pack(-side => "top", -anchor => "ne"); my $btn = $mw->Button(-command=> sub { $user->{firstname} = ''. localt +ime})->pack; MainLoop;` [download] Run it, click the button, be suitably impressed ;-P --Bob Niederman, http://bob-n.com	[reply] [d/l]
Re: Re: Updating values in Tk Toplevel object by jdtoronto (Prior) on Jul 18, 2003 at 03:35 UTC
That works fine! As soon as I got back and read your comments it became pretty darned obvious. I made the change in the DBI fetch subroutine and it all works just as I wanted it to. I suppose you could say that the variable is bound, but it isn't always the same variable! Many thanks! John	[reply]