如何使用WPF中的Unloaded事件对控件进行动画处理

Question

I hate to make another question so soon, but I can't seem to get this to work quite right.

I have a UserControl with a StoryBoard set to run when the Unloaded RoutedEvent occurs. However, I also have the code so that it will remove the the UserControl from its containing StackPanel when a button is clicked. What I would like to see happen is when that delete button is clicked, the StoryBoard runs, then the UserControl is removed from the StackPanel .

There's a lot of code already, so I'm not sure what to place. Let me know what code you want me to place for you to help me.

All I have is a RoutedEvent in the UserControl that raises the delete (or unload) event:

public static readonly RoutedEvent deleteEvent = 
            EventManager.RegisterRoutedEvent("delete", RoutingStrategy.Bubble,
            typeof(RoutedEventHandler), typeof(TimeEntry));

    private void raiseDeleteEvent()
    {
        RoutedEventArgs newDeleteEvent = new RoutedEventArgs(deleteEvent,this);
        RaiseEvent(newDeleteEvent);
    }

    private void deleteButton_Click(object sender, RoutedEventArgs e)
    {

        raiseDeleteEvent();
    }

then, two methods in the main window that registers to the event being thrown:

    private void entryAdder_Click(object sender, RoutedEventArgs e)
    {
        currentSession.addEntry(DateTime.Now);
        scrollStack.Children.Add(currentSession.currentTimeEntry);
        currentSession.currentTimeEntry.delete += currentTimeEntry_delete;
    }

    void currentTimeEntry_delete(object sender, RoutedEventArgs e)
    {
        scrollStack.Children.Remove(sender as TimeEntry);
    }

and finally, the UserControl , with its StoryBoard s:

        <Storyboard x:Key="Ondelete">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" Storyboard.TargetName="UserControl">
                <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="UserControl">
                <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>

Answer 1

I figured out how to solve my problem. I decided not to use the Unloaded event to make the animation, but instead procedurally code the animation, then have the UserControl subscribe to the Completed event of that DoubleAnimation , and finally trigger its own delete event, which would make anything subscribed to that event occur (ie the removal from the visual StackPanel and list of UserControl objects). This would allow the animation to run, and then, when it is finished, raise the deletion event.

Here's the mess of code for that. It's all pretty much summed up in these method calls. They're located within the UserControl :

public static readonly RoutedEvent deleteEvent = EventManager.RegisterRoutedEvent("delete", RoutingStrategy.Bubble,
    typeof(RoutedEventHandler), typeof(TimeEntry));

 private TransformGroup animatedTransform;
 private ScaleTransform animatedScale;

 private DoubleAnimation deleteDoubleAnimation;

 public UserControl()//the constructor
 {
     timeIn = DateTime.Now;
     timeSpent = timeOut - timeIn;
     this.InitializeComponent();
     setUpRenderTransform();
     setUpAnimationVariables();
     deleteDoubleAnimation.Completed += deleteDoubleAnimation_Completed;
 }

private void setUpRenderTransform()
{
    animatedTransform = new TransformGroup();
    animatedScale = new ScaleTransform();
    animatedTransform.Children.Add(animatedScale);

    this.RenderTransform = animatedTransform;

}

private void setUpAnimationVariables()
{
    deleteDoubleAnimation = new DoubleAnimation();
    deleteDoubleAnimation.To = 0;
    deleteDoubleAnimation.Duration = new Duration(TimeSpan.Parse("0:0:.25"));
}

private void raiseDeleteEvent()
{
    RoutedEventArgs newDeleteEvent = new RoutedEventArgs(deleteEvent, this);
    RaiseEvent(newDeleteEvent);
}

private void deleteButton_Click(object sender, RoutedEventArgs e)
{
    deleteAnimation();
}

void deleteDoubleAnimation_Completed(object sender, EventArgs e)
{
    raiseDeleteEvent();
}

private void deleteAnimation()
{
    animatedScale.BeginAnimation(ScaleTransform.ScaleXProperty, deleteDoubleAnimation);
    animatedScale.BeginAnimation(ScaleTransform.ScaleYProperty, deleteDoubleAnimation);
}