c# wpf使用绘制的矩形刷新画布

using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

namespace WpfApp
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void RefreshCanvas()
        {
            // 清空画布
            canvas.Children.Clear();

            // 创建矩形
            Rectangle rectangle = new Rectangle();
            rectangle.Width = 100;
            rectangle.Height = 100;
            rectangle.Fill = Brushes.Blue;

            // 设置矩形位置
            Canvas.SetLeft(rectangle, 50);
            Canvas.SetTop(rectangle, 50);

            // 将矩形添加到画布
            canvas.Children.Add(rectangle);
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            RefreshCanvas();
        }
    }
}