在可见性改变时激活故事板 [英] Activate Storyboard on Visibility Changed

问题描述

目前我有一个 Image，当它加载时我会脉冲.我想在更改图像的可见性时激活故事板.但我看到 Image.Triggers 必须是 EventTriggers.

Currently I have an Image that I pulse when it is loaded. I want to rather activate the Storyboard when I change the Visibility of the Image. But I see that Image.Triggers have to be EventTriggers.

我需要挂钩哪个事件?

<Image.Triggers>
    <EventTrigger RoutedEvent="Image.Loaded">
        <BeginStoryboard>
             <Storyboard>
                 <DoubleAnimation Storyboard.TargetName="MandateErrorImage"
                                  Storyboard.TargetProperty="Opacity"
                                  From="1.0" To="0.1" Duration="0:0:0.5"
                                  AutoReverse="True" RepeatBehavior="0:0:2" />
             </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
</Image.Triggers>

推荐答案

在 WPF 中有一个事件 UIElement.IsVisibleChanged 但是是CLR事件，不是路由事件，因此在EventTrigger中不能使用.

In WPF there is an event UIElement.IsVisibleChanged but is a CLR event, not a routed event, therefore in EventTrigger can not be used.

在这种情况下使用 IsVisible 属性如下:

In this case use IsVisible property in DataTrigger like this:

<Window.Resources>
    <Style x:Key="AnimationImageStyle" TargetType="{x:Type Image}">
        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=IsVisible}" 
                         Value="True">

                <DataTrigger.EnterActions>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetProperty="Opacity"
                                             From="1.0" To="0.1"
                                             Duration="0:0:0.5"
                                             AutoReverse="True"
                                             RepeatBehavior="0:0:2" />
                        </Storyboard>
                    </BeginStoryboard>
                </DataTrigger.EnterActions>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Window.Resources>

<Grid>
    <Image Name="TestImage" 
           Style="{StaticResource AnimationImageStyle}" 
           Source="Enter.jpg"
           Width="400"
           Height="400" />        
</Grid>

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