#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11118320
use warnings;
use Tk;

{ # start package
package Tk::ListBox3;

use List::Util qw( first );
use base qw/ Tk::Frame /;     # Frame-based composite
Construct Tk::Widget 'ListBox3'; # install MyNewWidget in pTk namespace

sub Populate                # called to build each widget instance
  {
  my($self, $args) = @_;
  $self->SUPER::Populate($args);

  my $frame = $self->Frame(
    -borderwidth => 5, -relief => 'ridge',
    )->pack(-fill=> 'both', -expand=> 1);
  my $label = $frame->Label( -fg => 'blue', -font => 30,
    )->pack(-fill => 'x');
  my $lbox = $frame->Scrolled(Listbox => -scrollbars => 'se',
    -height => 20,
    -selectforeground => 'orange',
    -selectbackground => 'steelblue4',
    -exportselection => 0,
    )->pack(-side => 'bottom', -fill => 'both', -expand=> 1);
  $frame->Entry(
    -validate => 'key', -validatecommand => sub
      {
      my ($want) = @_;
      length $want or return 1;
      my @list = $lbox->get(0 , "end");
      my $item = first { $list[$_] =~ /^\Q$want\E/ } 0 .. $#list;
      defined $item or return 0;
      $lbox->selectionClear( 0 , "end"  );
      $lbox->selectionSet($item);
      $lbox->see($item);
      1 # to allow
      },
    )->pack(-fill => 'x');

  $self->ConfigSpecs( DEFAULT => [$lbox], text => [$label],);

  $self->Delegates( Construct => $lbox, insert => $lbox,
    get => $lbox, curselection => $lbox );
  }

} # end package


my @choices = sort qw /alpha beta charlie delta echo foxtrot hotel india juliet
  kilo lima motel nancy oscar papa quebec radio sierra tango uniform victor
  whiskey xray yankee zulu oin gloin beorn gandalf elr ond eowyn/;
my $header_msg = "ENTER a KEY name: ";
my $selection;

my $mw = MainWindow->new;
$mw->geometry( '+900+250' );
$mw->title( 'Listbox' );

my $lb = $mw->ListBox3( -text => $header_msg,
  )->pack(-fill => 'both', -expand => 1,);
$lb->insert( 'end', @choices );

$mw->Button(-text => 'QUIT', -bg => 'red', -command => sub {
  $selection = $lb->get($lb->curselection);
  $mw->destroy
  },
  )->pack(-fill => 'x');

MainLoop;

defined $selection and print "'$selection' was selected\n";