WPF ListBoxItem ControlTemplate

<Window x:Class="WpfApp136.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp136"
        WindowState="Maximized"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <Style TargetType="ListBoxItem">
            <Setter Property="FontSize" Value="50"/>
            <Setter Property="HorizontalAlignment" Value="Stretch"/>
            <Setter Property="VerticalAlignment" Value="Center"/>            
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ListBoxItem}">
                        <Border Name="border"
                                Background="{TemplateBinding Background}"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="2"                                
                                Padding="5"
                                SnapsToDevicePixels="True"
                                Height="100">
                            <ContentPresenter/>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsSelected" Value="True">
                                <Setter TargetName="border"
                                        Property="Background"
                                        Value="Cyan"/>
                                <Setter TargetName="border"
                                        Property="BorderBrush"
                                        Value="Black"/>
                                <Setter TargetName="border"
                                        Property="Height"
                                        Value="240"/>
                                <Setter Property="FontSize"
                                        Value="100"/>
                            </Trigger>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter TargetName="border"
                                        Property="Background"
                                        Value="Red"/>
                                <Setter TargetName="border"
                                        Property="Height"
                                        Value="200"/>
                                <Setter TargetName="border"
                                        Property="BorderBrush"
                                        Value="Yellow"/>
                                <Setter TargetName="border"
                                        Property="BorderThickness"
                                        Value="10"/>
                                <Setter Property="FontSize"
                                        Value="80"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <ListBox x:Name="lbx"/>
    </Grid>
</Window>



//cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp136
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        int idx = 0;
        public MainWindow()
        {
            InitializeComponent();
            this.Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            System.Timers.Timer tmr = new System.Timers.Timer();
            tmr.Interval = 1000;
            tmr.Elapsed += Tmr_Elapsed;
            tmr.Start();
        }

        private void Tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            Application.Current?.Dispatcher.BeginInvoke(new Action(() =>
            {
                lbx.Items.Add($"{++idx},{Guid.NewGuid().ToString("N")}");
            }));            
        }
    }
}