WPF C# create canvas and draw ellipse in canvas

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 WpfApp17
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            Canvas cvs = new Canvas();
            this.WindowState = WindowState.Maximized;
            int width = (int)this.ActualWidth-60;
            int height = (int)this.ActualHeight-60;
            SolidColorBrush brush = new SolidColorBrush(Colors.Red);
            Random rnd = new Random();
            for (int i=0;i<150;i++)
            {
                Ellipse elp = new Ellipse();
                elp.Width = 50;
                elp.Height = 30;
                switch(i%4)
                {
                    case 0:
                        brush=new SolidColorBrush(Colors.Red);
                        break;
                    case 1:
                        brush = new SolidColorBrush(Colors.Green);
                        break;
                    case 2:
                        brush = new SolidColorBrush(Colors.Blue);
                        break;
                    case 3:
                        brush = new SolidColorBrush(Colors.Yellow);
                        break;
                }
                elp.Fill = brush;
                elp.Stroke=new SolidColorBrush(Colors.Black);
                elp.StrokeThickness = 5;
                Canvas.SetLeft(elp, rnd.Next(0, width));
                Canvas.SetTop(elp, rnd.Next(0, height));
                cvs.Children.Add(elp);
                //this.AddChild(cvs);
                this.Content = cvs;
            }
            
            //for(int i=0;i<width;i=i+10)
            //{
            //    for (int j = 0; j < height; j = j + 10)
            //    {
            //        Ellipse elp = new Ellipse();
            //        elp.Width = 5;
            //        elp.Height = 5;
            //        elp.Fill = brush;
            //        elp.StrokeThickness = 2;
            //        Canvas.SetLeft(elp, i);
            //        Canvas.SetTop(elp,j);
            //        cvs.Children.Add( elp );
            //    }
            //}
        }
    }
}

 private void MainWindow_Loaded(object sender, RoutedEventArgs e)
 {
     Canvas cvs = new Canvas();
     this.WindowState = WindowState.Maximized;
     int width = (int)this.ActualWidth-50;
     int height = (int)this.ActualHeight;
     SolidColorBrush brush = new SolidColorBrush(Colors.Red);
     Random rnd = new Random();

     for (int i = 0; i < width; i = i + 100)
     {
         for (int j = 0; j < height; j = j + 60)
         {
             Ellipse elp = new Ellipse();
             elp.Width = 50;
             elp.Height = 30;
             elp.Fill = brush;
             elp.StrokeThickness = 2;
             Canvas.SetLeft(elp, i);
             Canvas.SetTop(elp, j);
             cvs.Children.Add(elp);
         }
     }
     this.Content = cvs;
 }