首先 准备一个装饰器类 继承Adorner
1 /// <summary>
2 /// 装饰器必须继承抽象类Adorner
3 /// </summary>
4 public class CornerAdorner : Adorner
5 {
6 /// <summary>
7 /// 调用基类构造函数
8 /// </summary>
9 /// <param name="element"></param>
10 public CornerAdorner(UIElement element) : base(element)
11 {
12 }
13
14 /// <summary>
15 /// 重写绘制方法
16 /// </summary>
17 /// <param name="drawingContext"></param>
18 protected override void OnRender(DrawingContext drawingContext)
19 {
20 Rect rect = new Rect(this.AdornedElement.RenderSize);//装饰器所装饰的元素最终大小
21
22 Pen pen = new Pen(new SolidColorBrush(Colors.OrangeRed), 1);
23
24 drawingContext.DrawLine(pen, new Point(rect.TopLeft.X - 3, rect.TopLeft.Y - 3), new Point(rect.TopLeft.X + 5, rect.TopLeft.Y - 3));
25 drawingContext.DrawLine(pen, new Point(rect.TopLeft.X - 3, rect.TopLeft.Y - 3), new Point(rect.TopLeft.X - 3, rect.TopLeft.Y + 5));
26
27 drawingContext.DrawLine(pen, new Point(rect.TopRight.X + 3, rect.TopRight.Y - 3), new Point(rect.TopRight.X - 5, rect.TopRight.Y - 3));
28 drawingContext.DrawLine(pen, new Point(rect.TopRight.X + 3, rect.TopRight.Y - 3), new Point(rect.TopRight.X + 3, rect.TopRight.Y + 5));
29
30 drawingContext.DrawLine(pen, new Point(rect.BottomLeft.X - 3, rect.BottomLeft.Y + 3), new Point(rect.BottomLeft.X + 5, rect.BottomLeft.Y + 3));
31 drawingContext.DrawLine(pen, new Point(rect.BottomLeft.X - 3, rect.BottomLeft.Y + 3), new Point(rect.BottomLeft.X - 3, rect.BottomLeft.Y - 5));
32
33 drawingContext.DrawLine(pen, new Point(rect.BottomRight.X + 3, rect.BottomRight.Y + 3), new Point(rect.BottomRight.X - 5, rect.BottomRight.Y + 3));
34 drawingContext.DrawLine(pen, new Point(rect.BottomRight.X + 3, rect.BottomRight.Y + 3), new Point(rect.BottomRight.X + 3, rect.BottomRight.Y - 5));
35 }
36 }
界面
1 <Grid> 2 <StackPanel x:Name="stackPanel" 3 HorizontalAlignment="Center" 4 VerticalAlignment="Center" 5 Orientation="Vertical"> 6 <TextBox Width="200" Margin="15" /> 7 <TextBox Width="200" Margin="15" /> 8 <TextBox Width="200" Margin="15" /> 9 <TextBlock 10 Width="200" 11 Margin="15" 12 HorizontalAlignment="Center" 13 Text="边框测试" /> 14 <Button Margin="15" Content="添加边框" Click="Button_Click" /> 15 <Button Margin="15" Content="移除边框" Click="Button_Click_1" /> 16 </StackPanel> 17 </Grid>
点击事件
1 /// <summary>
2 /// 添加装饰器
3 /// </summary>
4 /// <param name="sender"></param>
5 /// <param name="e"></param>
6 private void Button_Click(object sender, RoutedEventArgs e)
7 {
8 foreach (UIElement element in stackPanel.Children)
9 {
10 if (element is TextBox || element is TextBlock)
11 {
12 var layer = AdornerLayer.GetAdornerLayer(element);//获取元素的装饰器层
13 layer.Add(new CornerAdorner(element));//把装饰器添加到层
14 }
15 }
16 }
17
18 /// <summary>
19 /// 移除装饰器
20 /// </summary>
21 /// <param name="sender"></param>
22 /// <param name="e"></param>
23 private void Button_Click_1(object sender, RoutedEventArgs e)
24 {
25 foreach (UIElement element in stackPanel.Children)
26 {
27 var layer = AdornerLayer.GetAdornerLayer(element);
28 var adorners = layer.GetAdorners(element);//获取控件上面的所有装饰器
29 if (adorners != null)
30 {
31 for (int i = adorners.Length - 1; i >= 0; i--)
32 {
33 Adorner adorner = adorners[i];
34 layer.Remove(adorner);//移除装饰器
35 }
36 }
37 }
38 }
效果
如果要实现点击才出现这个边框，可参考此内容