ListBox show image and refresh automatically via System.Timers.Timer per 1 millisecond

<Window x:Class="WpfApp403.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:WpfApp403"
        mc:Ignorable="d"
        WindowState="Maximized"
        AllowsTransparency="True"
        WindowStyle="None"
        KeyDown="Window_KeyDown"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <ListBox x:Name="lbx"
                 ItemsSource="{Binding Books,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                 SelectedIndex="{Binding SelectedIdx,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                 VirtualizingPanel.IsContainerVirtualizable="True"
                 VirtualizingPanel.IsVirtualizing="True"
                 VirtualizingPanel.VirtualizationMode="Recycling"
                 VirtualizingPanel.CacheLength="1"
                 VirtualizingPanel.CacheLengthUnit="Item">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Image Source="{Binding ImgUrl}"
                               RenderOptions.BitmapScalingMode="Fant"
        Width="{Binding ActualWidth,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}}}"
        Height="{Binding ActualHeight,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}}}"/>
                        <TextBlock HorizontalAlignment="Right"
                                   VerticalAlignment="Bottom"
                                   Width="200"
                                   Height="100"                                   
                                   Foreground="Red"
                                   FontSize="50"
                                   Text="{Binding Id}"
                                   Panel.ZIndex="2"/>
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>


//using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
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;
using System.IO;
using System.ComponentModel;

namespace WpfApp403
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
            InitData();
            System.Timers.Timer tmr = new System.Timers.Timer();
            tmr.Elapsed += Tmr_Elapsed;
            tmr.Interval = 1;
            tmr.Start();                        
            SizeChanged += MainWindow_SizeChanged;
            Application.Current.DispatcherUnhandledException += Current_DispatcherUnhandledException;           
        }

        private void InitData()
        {
            Books = new ObservableCollection<Book>();
            var imgsList = Directory.GetFiles(@"../../Images");
            if (imgsList != null && imgsList.Any())
            {
                int imgsCount = imgsList.Count();
                for (int i = 0; i < 1000000; i++)
                {
                    Books.Add(new Book()
                    {
                        Id = i + 1,
                        ImgUrl = imgsList[i % imgsCount]
                    });
                }
            }
        }

        private void Tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (++SelectedIdx >= books.Count)
            {
                SelectedIdx = 0;                
            }
            System.Diagnostics.Debug.WriteLine(SelectedIdx);
            Application.Current.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Send,new Action(() =>
            {
                lbx.ScrollIntoView(lbx.SelectedItem);
            }));
        }

        private ObservableCollection<Book> books;
        public ObservableCollection<Book> Books
        {
            get
            {
                return books;
            }
            set
            {
                if (value != books)
                {
                    books = value;
                    OnPropertyChanged(nameof(Books));
                }
            }
        }

        private int selectedIdx;
        public int SelectedIdx
        {
            get
            {
                return selectedIdx;
            }
            set
            {
                if (value != selectedIdx)
                {
                    selectedIdx = value;
                    OnPropertyChanged(nameof(SelectedIdx));
                }
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propName)
        {
            var handler = PropertyChanged;
            if (handler != null)
            {
                handler?.Invoke(this, new PropertyChangedEventArgs(propName));
            }
        }

        private void Current_DispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)
        {
            MessageBox.Show(e.Exception.Message);
        }

        private void MainWindow_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            Width = SystemParameters.PrimaryScreenWidth;
            Height = SystemParameters.PrimaryScreenHeight;
        }

        private void Window_KeyDown(object sender, KeyEventArgs e)
        {
            if ((Keyboard.Modifiers == ModifierKeys.Control) && e.Key == Key.C)
            {
                var msgResult = MessageBox.Show("Are you sure to exit?", "Exit",
                    MessageBoxButton.YesNo, MessageBoxImage.Question);
                if (msgResult == MessageBoxResult.Yes)
                {
                    this.Close();
                }
            }
        }
    }



    public class BooksData : ObservableCollection<Book>
    {
        public BooksData()
        {
            var imgsList = Directory.GetFiles(@"../../Images");
            if (imgsList != null && imgsList.Any())
            {
                int imgsCount = imgsList.Count();
                for (int i = 0; i < 10000; i++)
                {
                    this.Add(new Book()
                    {
                        Id = i + 1,
                        ImgUrl = imgsList[i % imgsCount]
                    });
                }
            }
        }
    }

    public class Book
    {
        public int Id { get; set; }

        public string ImgUrl { get; set; }
    }
}