If I understand your question, then would this help?

#!/usr/bin/perl

use strict;
use warnings;
use Tk;
use Tk::JComboBox;
use File::Glob ();

my $wMain = MainWindow->new;
my $cboFile = $wMain->JComboBox(
    
)->pack(-padx => 30, -pady => 30);

foreach $_ (glob('*')) {
  $cboFile->addItem($_);
}

MainLoop;
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