将行为附加到Silverlight中的所有TextBox

1 回答

• 8

  您可以覆盖应用中TextBoxes的默认样式 . 然后在这种风格中，您可以使用某种方法将行为应用于setter（通常使用附加属性） .

  它会是这样的：

  <Application.Resources>
      <Style TargetType="TextBox">
          <Setter Property="local:TextBoxEx.SelectAllOnFocus" Value="True"/>
      </Style>
  </Application.Resources>
  

  行为实现：

  public class TextBoxSelectAllOnFocusBehavior : Behavior<TextBox>
  {
      protected override void OnAttached()
      {
          base.OnAttached();
  
          this.AssociatedObject.GotMouseCapture += this.OnGotFocus;
          this.AssociatedObject.GotKeyboardFocus += this.OnGotFocus;
      }
  
      protected override void OnDetaching()
      {
          base.OnDetaching();
  
          this.AssociatedObject.GotMouseCapture -= this.OnGotFocus;
          this.AssociatedObject.GotKeyboardFocus -= this.OnGotFocus;
      }
  
      public void OnGotFocus(object sender, EventArgs args)
      {
          this.AssociatedObject.SelectAll();
      }
  }
  

  附加属性可以帮助我们应用这些行为：

  public static class TextBoxEx
  {
      public static bool GetSelectAllOnFocus(DependencyObject obj)
      {
          return (bool)obj.GetValue(SelectAllOnFocusProperty);
      }
      public static void SetSelectAllOnFocus(DependencyObject obj, bool value)
      {
          obj.SetValue(SelectAllOnFocusProperty, value);
      }
      public static readonly DependencyProperty SelectAllOnFocusProperty =
          DependencyProperty.RegisterAttached("SelectAllOnFocus", typeof(bool), typeof(TextBoxSelectAllOnFocusBehaviorExtension), new PropertyMetadata(false, OnSelectAllOnFocusChanged));
  
  
      private static void OnSelectAllOnFocusChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
      {
          var behaviors = Interaction.GetBehaviors(sender);
  
          // Remove the existing behavior instances
          foreach (var old in behaviors.OfType<TextBoxSelectAllOnFocusBehavior>().ToArray())
              behaviors.Remove(old);
  
          if ((bool)args.NewValue)
          {
              // Creates a new behavior and attaches to the target
              var behavior = new TextBoxSelectAllOnFocusBehavior();
  
              // Apply the behavior
              behaviors.Add(behavior);
          }
      }
  }
  

  回复于 2024-05-02T08:50:42+08:00