WPF Canvas show custom control with ellipse filled with image and text,peridoically update via Syste

//custom control
<UserControl x:Class="WpfApp389.ElpImageTbk"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:WpfApp389"
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800">
    <Grid>
        <Ellipse Fill="{Binding UCFillImgBrush,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                     />
        <TextBlock Text="{Binding UCElpStr,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                   HorizontalAlignment="Center"
                   VerticalAlignment="Center"
                   FontSize="50"
                   Foreground="Red"/>
    </Grid>
</UserControl>


//custom control.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 WpfApp389
{
    /// <summary>
    /// Interaction logic for ElpImageTbk.xaml
    /// </summary>
    /// 
    
    public partial class ElpImageTbk : UserControl
    {
        public ElpImageTbk()
        {
            InitializeComponent();
            this.DataContext = this;
        }



        public ImageBrush UCFillImgBrush
        {
            get { return (ImageBrush)GetValue(UCFillImgBrushProperty); }
            set { SetValue(UCFillImgBrushProperty, value); }
        }

        // Using a DependencyProperty as the backing store for UCFillImgBrush.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty UCFillImgBrushProperty =
            DependencyProperty.Register("UCFillImgBrush", typeof(ImageBrush), 
                typeof(ElpImageTbk), new PropertyMetadata(null));





        public string UCElpStr
        {
            get { return (string)GetValue(UCElpStrProperty); }
            set { SetValue(UCElpStrProperty, value); }
        }

        // Using a DependencyProperty as the backing store for UCElpStr.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty UCElpStrProperty =
            DependencyProperty.Register("UCElpStr", typeof(string), 
                typeof(ElpImageTbk), new PropertyMetadata(""));





    }
}



//xaml.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;
using System.IO;

namespace WpfApp389
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private Grid gd { get; set; }
        private Button btn { get; set; }
        private Canvas cvs { get; set; }
        private Random rnd { get; set; }
        private int width { get; set; }
        private int height { get; set; }
        private System.Timers.Timer tmr { get; set; }

        private bool IsPaused = false;

        public MainWindow()
        {
            InitializeComponent();
            this.WindowState = WindowState.Maximized;
            gd = new Grid();
            btn = new Button();
            Grid.SetRow(btn, 0);
            Grid.SetColumn(btn, 0);
            btn.Width = 200;
            btn.Height = 50;
            btn.FontSize = 30;
            btn.Foreground = new SolidColorBrush(Colors.Red);
            btn.Content = "Pause";
            btn.Click += Btn_Click;
            btn.TabIndex = 2;
            btn.HorizontalAlignment = HorizontalAlignment.Right;
            btn.VerticalAlignment = VerticalAlignment.Top;
            if (!gd.Children.Contains(btn))
            {
                gd.Children.Add(btn);
            }
            cvs = new Canvas();
            if (!gd.Children.Contains(cvs))
            {
                gd.Children.Add((cvs));
            }
            rnd = new Random();
            this.Content = gd;
            this.Loaded += MainWindow_Loaded;

        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            width = (int)this.ActualWidth-100;
            height= (int)this.ActualHeight-100;
            RefreshData();
            tmr = new System.Timers.Timer();
            tmr.Elapsed += Tmr_Elapsed;
            tmr.Interval = 2000;
            tmr.Start();
        }

        private void Tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if(IsPaused)
            {
                return;
            }
            Application.Current.Dispatcher.BeginInvoke(new Action(() =>
            {
                RefreshData();
            }));            
        }

        private void Btn_Click(object sender, RoutedEventArgs e)
        {
            IsPaused = !IsPaused;
            if(IsPaused)
            {
                btn.Content = "Resume";
            }
            else
            {
                btn.Content = "Pause";
            }
        }

        private void RefreshData()
        {
            if (cvs != null)
            {               
                cvs.Children.Clear();

                var imgsList = Directory.GetFiles(@"../../Images");
                if(imgsList!=null && imgsList.Any())
                {
                    int imgsCnt = imgsList.Count();
                    for(int i=0;i<50;i++)
                    {
                        ElpImageTbk elpImg = new ElpImageTbk();
                        elpImg.Width = 100;
                        elpImg.Height = 50;
                        BitmapImage bmp = new BitmapImage();
                        bmp.BeginInit();
                        bmp.UriSource=new Uri(imgsList[i%imgsCnt], UriKind.RelativeOrAbsolute);
                        bmp.EndInit();
                        bmp.Freeze();
                        elpImg.UCFillImgBrush = new ImageBrush(bmp);
                        elpImg.UCElpStr=(i+1).ToString();
                        Canvas.SetLeft(elpImg, rnd.Next(0, width));
                        Canvas.SetTop(elpImg, rnd.Next(0, height));
                        if(!cvs.Children.Contains(elpImg))
                        {
                            cvs.Children.Add(elpImg);
                        }
                    }
                }
            }
        }
    }
}