public class my : Canvas
    {
        
     public   my()
        {
            Brush b = Brushes.Blue;
            this.Background = b;
            DrawingVisual visual = new DrawingVisual();
            DrawingContext con = visual.RenderOpen();
            Pen p = new Pen(Brushes.Brown,3);
         con.DrawLine(p, new Point(0, 0), new Point(25, 25));
         ovals.Add(visual);
         this.AddVisualChild(visual);
        }
        private List<Visual> ovals = new List<Visual>();
        public void addoval(Visual new_)
        {
         
           
            ovals.Add(new_);
            base.AddVisualChild(new_);
            base.AddLogicalChild(new_);

        }
    }

 private void button1_Click(object sender, RoutedEventArgs e)
        {
            DrawingVisual visual = new DrawingVisual();
            Brush b=Brushes.Blue;
           
            DrawingContext context = visual.RenderOpen();
            
                context.DrawEllipse(b,null, new Point(10, 10), 20, 20);
                //userControl11.addoval(visual);
               my h = new my();
               h.Height = 500;
               h.Width = 500;
                canvas1.Children.Add(h);
                h.addoval(visual);
            
        }