Fading out a window

问题:

I am currently developing a wpf c# application. I have added to event triggers to the xaml of the form to fade in when the window loads and fades out when the window closes.

The fading in works perfectly without any problems but the fading out is not working.

I have it set up so the window fades in when it loads, has a timer to last 5 seconds, and then calls the form fade out event.

However, the window doesn't fade out it just closes straight away no animation. Below is the code I have for the fade in and fade out events

<Window.Triggers>
        <EventTrigger RoutedEvent="Window.Loaded">
            <BeginStoryboard>
                <Storyboard Name="FormFade">
                    <DoubleAnimation Name="FormFadeAnimation"
                                     Storyboard.TargetProperty="(Window.Opacity)"
                                     From="0.0" To="1.0" Duration="0:0:1"
                                     AutoReverse="False" RepeatBehavior="1x" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="Window.Unloaded">
            <BeginStoryboard>
                <Storyboard Name="FormFadeOut" Completed="FormFadeOut_Completed">
                    <DoubleAnimation Name="FormFadeOutAnimation"
                                     Storyboard.TargetName="FormFadeOut"
                                     Storyboard.TargetProperty="(Window.Opacity)"
                                     From="1.0" To="0.0" Duration="0:0:1"
                                     AutoReverse="False" RepeatBehavior="1x" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Window.Triggers>

Thanks for any help you can offer.

回答1:

Unloaded is not a suitable event for this, i'm not sure if this event can even occur for windows. You need to handle Closing, prevent it from actually closing, start an animation and close it when the Completed event of the animation occurs.

e.g.

<Window ...
        Closing="Window_Closing">

private void Window_Closing(object sender, CancelEventArgs e)
{
    Closing -= Window_Closing;
    e.Cancel = true;
    var anim = new DoubleAnimation(0, (Duration)TimeSpan.FromSeconds(1));
    anim.Completed += (s, _) => this.Close();
    this.BeginAnimation(UIElement.OpacityProperty, anim);
}

回答2:

just try this sample

<Window x:Class="FadeInAndOutWindow.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300" Closing="Window_Closing" x:Name="winHelp">
<Window.Triggers>
    <EventTrigger RoutedEvent="Window.Loaded">
        <BeginStoryboard>
            <Storyboard Name="FormFade">
                <DoubleAnimation  Name="FormFadeAnimation"
                                  Storyboard.TargetName="winHelp"
                                  Storyboard.TargetProperty="(Window.Opacity)"
                                  From="0.0"
                                  To="1.0"
                                  Duration="0:0:1"
                                  AutoReverse="False"
                                  RepeatBehavior="1x" />
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
    <EventTrigger RoutedEvent="Window.Unloaded">
        <BeginStoryboard>
            <Storyboard Name="FormFadeOut"
                        Completed="FormFadeOut_Completed">
                <DoubleAnimation  Name="FormFadeOutAnimation"
                                  Storyboard.TargetName="winHelp"
                                  Storyboard.TargetProperty="(Window.Opacity)"
                                  From="1.0"
                                  To="0.0"
                                  Duration="0:0:1"
                                  AutoReverse="False"
                                  RepeatBehavior="1x" />
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
</Window.Triggers>    
<Grid>

</Grid>

namespace FadeInAndOutWindow
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private bool closeCompleted = false;


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

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {

            if (!closeCompleted)
            {
                FormFadeOut.Begin();
                e.Cancel = true;
            }
        }

    }
}

回答3:

H.B. solution is good but don't close effectively the window because Close() call window_Closing and loop. Here my working solution:

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        AlreadyFaded = false;
    }

    bool AlreadyFaded;
    private void window_Closing(object sender, CancelEventArgs e)
    {
        if (!AlreadyFaded)
        {
            AlreadyFaded = true;
            e.Cancel = true;
            var anim = new DoubleAnimation(0, (Duration)TimeSpan.FromSeconds(1));
            anim.Completed += new EventHandler(anim_Completed);
            this.BeginAnimation(UIElement.OpacityProperty, anim);
        }
    }

    void anim_Completed(object sender, EventArgs e)
    {
         Close();
    }