UWP UserControl with Canvas:你怎么画？

<UserControl
    x:Class="YourNamespace.YourUserControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:YourNamespace">

    <Grid>
        <Canvas x:Name="canvas" Width="400" Height="400"/>
    </Grid>
</UserControl>

using Windows.UI;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Shapes;

namespace YourNamespace
{
    public sealed partial class YourUserControl : UserControl
    {
        public YourUserControl()
        {
            this.InitializeComponent();
            this.Loaded += UserControl_Loaded;
        }

        private void UserControl_Loaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        {
            // 创建一个矩形
            Rectangle rectangle = new Rectangle
            {
                Width = 200,
                Height = 100,
                Fill = new SolidColorBrush(Colors.Blue),
                Stroke = new SolidColorBrush(Colors.Black),
                StrokeThickness = 2
            };

            // 将矩形添加到Canvas中
            canvas.Children.Add(rectangle);

            // 设置矩形在Canvas中的位置
            Canvas.SetLeft(rectangle, 100);
            Canvas.SetTop(rectangle, 100);
        }
    }
}