WPF customize ellipse fill with image/imagebrush and show text

//xaml
<UserControl x:Class="WpfApp250.BookControl"
             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:WpfApp250"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <Ellipse Fill="{Binding ElpBrush,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
        <TextBlock Text="{Binding ElpStr,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                   HorizontalAlignment="Center" VerticalAlignment="Center"/>
    </Grid>
</UserControl>


//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 WpfApp250
{
    /// <summary>
    /// Interaction logic for BookControl.xaml
    /// </summary>
    public partial class BookControl : UserControl
    {
        public BookControl()
        {
            InitializeComponent();
            this.DataContext = this;
        }

        public ImageBrush ElpBrush
        {
            get { return (ImageBrush)GetValue(ElpBrushProperty); }
            set { SetValue(ElpBrushProperty, value); }
        }

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

        public string  ElpStr
        {
            get { return (string )GetValue(ElpStrProperty); }
            set { SetValue(ElpStrProperty, value); }
        }

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


    }
}

//xaml
<UserControl x:Class="WpfApp250.BookControl"
             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:WpfApp250"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <Ellipse Fill="{Binding ElpBrush,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
        <TextBlock Text="{Binding ElpStr,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                   HorizontalAlignment="Center" VerticalAlignment="Center"/>
    </Grid>
</UserControl>


//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 WpfApp250
{
    /// <summary>
    /// Interaction logic for BookControl.xaml
    /// </summary>
    public partial class BookControl : UserControl
    {
        public BookControl()
        {
            InitializeComponent();
            this.DataContext = this;
        }

        public ImageBrush ElpBrush
        {
            get { return (ImageBrush)GetValue(ElpBrushProperty); }
            set { SetValue(ElpBrushProperty, value); }
        }

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

        public string  ElpStr
        {
            get { return (string )GetValue(ElpStrProperty); }
            set { SetValue(ElpStrProperty, value); }
        }

        // Using a DependencyProperty as the backing store for ElpStr.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty ElpStrProperty =
            DependencyProperty.Register("ElpStr", typeof(string), 
                typeof(BookControl), 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;

namespace WpfApp250
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        Random rnd = new Random();
        public MainWindow()
        {
            InitializeComponent();
            this.WindowState = WindowState.Maximized;
            this.Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            int width = (int)this.ActualWidth;
            int height= (int)this.ActualHeight;
            Canvas cvs = new Canvas();
            List<string> imgsList = new List<string>(System.IO.Directory.GetFiles(@"../../Images"));
            int len = imgsList.Count;
            for (int i = 0; i < 10; i++)
            {
                BookControl bk = new BookControl();
                ImageBrush imgBrush = new ImageBrush();
                imgBrush.ImageSource = new BitmapImage(new Uri(imgsList[i], UriKind.RelativeOrAbsolute));
                bk.ElpBrush = imgBrush;
                bk.ElpStr =$"{i+1},{DateTime.Now.ToString("yyyyMMddHHmmssffff")}";
                bk.Width = 300;
                bk.Height = 200;
                Canvas.SetLeft(bk, rnd.Next(0,width - 300));
                Canvas.SetTop(bk, rnd.Next(height - 300));
                if(!cvs.Children.Contains(bk))
                {
                    cvs.Children.Add(bk);
                } 
            }
            this.Content = cvs;
        }
    }
}