Question

I make a Wpf-modeless-reusable window with showing animation. It’ was reused for loading performance. And then a new problem has occured.

At first, it is a MainWindow’s code behind. win1 is instance of popup window.

public partial class MainWindow : Window
{

    Window1 win1 = new Window1();

    public MainWindow() { InitializeComponent(); }

    private void button1_Click(object sender, RoutedEventArgs e) { win1.Owner = this; win1.Show(); }
    private void button2_Click(object sender, RoutedEventArgs e) { win1.Hide(); }
    private void Window_Closed(object sender, EventArgs e) { win1.Close(); }
}

And here is a popup window’s xaml…

<Window x:Class="WpfApplication4.Window1" x:Name="win"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="300" Width="300" ShowActivated="False" Background="#00000000" AllowsTransparency="True" WindowStyle="None" IsVisibleChanged="Window_IsVisibleChanged">
    <Window.Resources>
        <Storyboard x:Key="aniShowing" FillBehavior="Stop">
            <ParallelTimeline BeginTime="0:0:0" Duration="0:0:2">
                <DoubleAnimation Storyboard.TargetName="win" Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:2"/>
            </ParallelTimeline>
        </Storyboard>

    </Window.Resources>
    <Ellipse Fill="Red"/>
</Window>

… and finally, here is a code behind of popup window.

public partial class Window1 : Window
{

    Storyboard aniShowing;

    public Window1()
    {
        InitializeComponent();
        aniShowing = (Storyboard)this.Resources["aniShowing"];
    }

    private void Window_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        if ((bool)e.NewValue == true) { this.BeginStoryboard(aniShowing); }
        else { aniShowing.Remove(this); this.Opacity = 0; }
    }
}

I want to show showing animation at Window_IsVisibleChanged. It works very well. But it’s a first time only.

In second time, win1 showed with blink at shortly, and animation was played.

third time, fourth time looks like second time, too.

how can i get rid this mysterious blink?

Answer 1

I’m guessing your problem actually is that you don’t have a animation that fades out the said window, so when the button1 is clicked, it does the animation,

Storyboard.TargetProperty="Opacity" From="0" To="1"

Whatever the state it is in, it will go from 0 to 1, you see a “blink” that sets it to 0 before the animation can apply if it’s already at 1.

To get rid of it, do the reverse animation when the window is closed (Opacity from 1 to 0 on button2 click i believe).

PS: Hide() is the same as setting win.Visibility = Visibility.Hidden; you didn’t take into account Visibility.Collapsed.