c# - Fading out a wpf window on close

Question

I want to fade a window in/out in my application.
Fading in occurs on Window.Loaded and I wanted to fade out on close (Window.Closed or Window.Closing). Fading in works perfectly, but Window.Closing is not allowed value for RoutedEvent property.
What RoutedEvent should I be using for Close?

    <Window.Triggers>
        <EventTrigger RoutedEvent="Window.Loaded">
            <BeginStoryboard>
                <Storyboard>
                    <DoubleAnimation Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:2" FillBehavior="HoldEnd" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="Window.Closing">
            <BeginStoryboard>
                <Storyboard>
                    <DoubleAnimation Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="0:0:2" FillBehavior="HoldEnd" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Window.Triggers>

I get a error on , Value 'Window.Closing' cannot be assigned to property 'RoutedEvent'. Invalid event name.

Answer 1

Closing is not a routed event, so you can't use it in an EventTrigger. Perhaps you could start the storyboard in the handler of the ClosingEvent in the code-behind and cancel the event... something like that :

private bool closeStoryBoardCompleted = false;

private void Window_Closing(object sender, CancelEventArgs e)
{
    if (!closeStoryBoardCompleted)
    {
        closeStoryBoard.Begin();
        e.Cancel = true;
    }
}

private void closeStoryBoard_Completed(object sender, EventArgs e)
{
    closeStoryBoardCompleted = true;
    this.Close();
}