WPF 使用行为<Behavior>实现SAP焦点样式

效果

首先添加引用 System.Windows.Interactivity.WPF （需要用nuget包下载)

准备一个行为类 继承Behavior类

 1 /// <summary>
 2     /// 控件获取焦点后的行为
 3     /// </summary>
 4     public class FocusBehavior : Behavior<FrameworkElement>
 5     {
 6         protected override void OnAttached()
 7         {
 8             base.OnAttached();
 9             AssociatedObject.GotFocus += AssociatedObject_GotFocus;//获取焦点的事件
10             AssociatedObject.LostFocus += AssociatedObject_LostFocus;//失去焦点的时间
11         }
12 
13         protected override void OnDetaching()
14         {
15             base.OnDetaching();
16             AssociatedObject.GotFocus -= AssociatedObject_GotFocus;//移除
17             AssociatedObject.LostFocus -= AssociatedObject_LostFocus;//移除
18         }
19 
20         private void AssociatedObject_GotFocus(object sender, RoutedEventArgs e)
21         {
22             var control = sender as FrameworkElement;
23             var layer = AdornerLayer.GetAdornerLayer(control);
24             layer.Add(new CornerAdorner(control));//这里就用以前实现的装饰器类
25         }
26 
27         private void AssociatedObject_LostFocus(object sender, RoutedEventArgs e)
28         {
29             var control = sender as FrameworkElement;
30             var layer = AdornerLayer.GetAdornerLayer(control);
31             var adorners = layer.GetAdorners(control);
32             if (adorners != null)
33             {
34                 for (int i = adorners.Length - 1; i >= 0; i--)
35                 {
36                     layer.Remove(adorners[i]);
37                 }
38             }
39         }
40     }

界面引用命名空间

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

界面内容

 1 <Grid>
 2         <StackPanel
 3             x:Name="stackPanel"
 4             HorizontalAlignment="Center"
 5             VerticalAlignment="Center"
 6             Orientation="Vertical">
 7             <TextBox Width="200" Margin="15">
 8                 <i:Interaction.Behaviors>
 9                     <local:FocusBehavior />
10                 </i:Interaction.Behaviors>
11             </TextBox>
12             <CheckBox Margin="15" Content="点击">
13                 <i:Interaction.Behaviors>
14                     <local:FocusBehavior />
15                 </i:Interaction.Behaviors>
16             </CheckBox>
17             <TextBox Width="200" Margin="15" />
18             <TextBox Width="200" Margin="15" />
19             <Button Margin="15" Content="确定">
20                 <i:Interaction.Behaviors>
21                     <local:FocusBehavior />
22                 </i:Interaction.Behaviors>
23             </Button>
24 
25             <TextBlock
26                 Width="200"
27                 Margin="15"
28                 HorizontalAlignment="Center"
29                 Text="边框测试">
30                 <i:Interaction.Behaviors>
31                     <local:FocusBehavior />
32                 </i:Interaction.Behaviors>
33             </TextBlock>
34         </StackPanel>
35     </Grid>

标签：control,layer,LostFocus,样式,AssociatedObject,GotFocus,var,WPF,SAP
来源： https://www.cnblogs.com/AtTheMoment/p/14960832.html