有的时候，给指定的控件，追加一个装饰器Adorner，备注下

有的时候，给指定的控件，追加一个装饰器Adorner，备注下

比如给某个图片加个工具条等等...都可以采用装饰器的方式来实现，复用性高，易维护，特此备注下

整体效果如下：

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 AdornerDemo
{
    /// 

    /// MainWindow.xaml 的交互逻辑
    /// 
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            var ad = AdornerLayer.GetAdornerLayer(tb);
            ad.Add(new CustomAdorner(tb));
        }
    }
}

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.Documents;
using System.Windows.Input;
using System.Windows.Media;

namespace AdornerDemo
{
    class CustomAdorner : Adorner
    {
        VisualCollection _visuals;
        Canvas _canvas;
        TextBlock block;

        public CustomAdorner(UIElement adornedElement) : base(adornedElement)
        {
            _visuals = new VisualCollection(this);
            block = new TextBlock();
            block.Text = "√";
            block.Cursor = Cursors.Hand;
            block.MouseLeftButtonUp += Block_MouseLeftButtonUp;

            _canvas = new Canvas();
            _canvas.Children.Add(block);
            _visuals.Add(_canvas);
        }

        private void Block_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            MessageBox.Show("xl");
        }

        protected override int VisualChildrenCount => _visuals.Count;

        protected override Visual GetVisualChild(int index)
        {
            return _visuals[index];
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            _canvas.Arrange(new Rect(finalSize));
            block.Margin = new Thickness(finalSize.Width + 3, 0, 0, 0);
            return base.ArrangeOverride(finalSize);
        }
    }
}