好的,我最终写下了我自己的行为
namespace MyNamespace
{
public class CommentBehavior : Behavior<TextBox>
{
private readonly TimeSpan howLongWeWaitBeforePopupCloses = TimeSpan.FromMilliseconds(200);
private DispatcherTimer popupClosingTimer;
public static DependencyProperty PopupProperty = DependencyProperty.Register("Popup", typeof(Popup), typeof(CommentBehavior), new PropertyMetadata(null));
public Popup Popup
{
get { return (Popup)this.GetValue(PopupProperty); }
set { this.SetValue(PopupProperty, value); }
}
protected override void OnAttached()
{
this.popupClosingTimer = new DispatcherTimer();
this.popupClosingTimer.Stop();
this.popupClosingTimer.Interval = howLongWeWaitBeforePopupCloses;
this.popupClosingTimer.Tick += this.ClosePopup;
this.AssociatedObject.GotFocus += this.GotFocus;
this.AssociatedObject.LostFocus += this.LostFocus;
this.Popup.Child.GotFocus += PopupChild_GotFocus;
this.Popup.Child.LostFocus += PopupChild_LostFocus;
}
private void PopupChild_LostFocus(object sender, RoutedEventArgs e)
{
this.popupClosingTimer.Start();
}
private void PopupChild_GotFocus(object sender, RoutedEventArgs e)
{
this.popupClosingTimer.Stop();
}
protected override void OnDetaching()
{
this.AssociatedObject.GotFocus -= this.GotFocus;
this.AssociatedObject.LostFocus -= this.LostFocus;
this.Popup.GotFocus -= PopupChild_GotFocus;
this.popupClosingTimer.Tick -= this.ClosePopup;
this.popupClosingTimer = null;
}
private void ClosePopup(object sender, EventArgs e)
{
this.Popup.IsOpen = false;
this.popupClosingTimer.Stop();
}
protected void GotFocus(object sender, RoutedEventArgs e)
{
this.popupClosingTimer.Stop();
this.Popup.IsOpen = true;
var at = this.CalculatePopupPosition();
this.Popup.HorizontalOffset = at.X;
this.Popup.VerticalOffset = at.Y;
}
private Point CalculatePopupPosition()
{
var owner = this.AssociatedObject;
var transformation = owner.TransformToVisual(Application.Current.RootVisual);
var at = transformation.Transform(new Point(owner.ActualWidth, 0));
return at;
}
protected void LostFocus(object sender, RoutedEventArgs e)
{
this.popupClosingTimer.Start();
}
}
}
以及以下 XAML
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<StackPanel Grid.Row="0" Background="Red">
<TextBox Width="200" Text="0.01">
<i:Interaction.Behaviors>
<local:CommentBehavior>
<local:CommentBehavior.Popup>
<Popup>
<TextBox Text="Comment" />
</Popup>
</local:CommentBehavior.Popup>
</local:CommentBehavior>
</i:Interaction.Behaviors>
</TextBox>
</StackPanel>
</Grid>