wpf - 如何让wpf中的文本 block 闪烁？

Question

我正在 WPF 中创建一个仪表板，其中包含一堆关键绩效指标，每个指标都包含三个值。

每当值发生变化时，我希望用户控件闪烁 5 秒钟。我想让控件的背景色切换文本 block 的前景色，并将文本 block 的前景色更改为用户控件的背景色。

整个 WPF 动画对我来说是新的，因此我们将不胜感激!

我的用户控件如下所示:

    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="10" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="10" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>

    <TextBlock x:Name="TitleTextBlock" Text="Title" FontSize="32" HorizontalAlignment="Center" Grid.Row="0" FontFamily="OCR-A II" Foreground="White" VerticalAlignment="Bottom" />
    <TextBlock x:Name="Value1TextBlock" Text="0" FontSize="192" HorizontalAlignment="Center" Grid.Row="2" FontFamily="OCR-A II" VerticalAlignment="Center" Foreground="White" />
    <TextBlock x:Name="Value2TextBlock" Text="0" FontSize="32" HorizontalAlignment="Center" Grid.Row="4" FontFamily="OCR-A II" Foreground="White" VerticalAlignment="Top" />

</Grid>

Answer 1

要使 TextBlock 在其文本更改时闪烁，您可以使用 ColorAnimationUsingKeyFrames。文本绑定(bind)到名为 TextTitle 的属性。

<Window.Resources>
    <Storyboard x:Key="blinkAnimation" Duration="0:0:5" >
        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)"
                                      Storyboard.TargetName="TitleTextBlock"
                                      AutoReverse="True">
            <ColorAnimationUsingKeyFrames.KeyFrames>
                <DiscreteColorKeyFrame KeyTime="0:0:0" Value="White"/>
                <DiscreteColorKeyFrame KeyTime="0:0:1" Value="Black"/>
                <DiscreteColorKeyFrame KeyTime="0:0:2" Value="White"/>
                <DiscreteColorKeyFrame KeyTime="0:0:3" Value="Black"/>
                <DiscreteColorKeyFrame KeyTime="0:0:4" Value="White"/>
            </ColorAnimationUsingKeyFrames.KeyFrames>
        </ColorAnimationUsingKeyFrames>

        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(TextBlock.Foreground).(SolidColorBrush.Color)"
                                      Storyboard.TargetName="TitleTextBlock"
                                      AutoReverse="True">
            <ColorAnimationUsingKeyFrames.KeyFrames>
                <DiscreteColorKeyFrame KeyTime="0:0:0" Value="Black"/>
                <DiscreteColorKeyFrame KeyTime="0:0:1" Value="White"/>
                <DiscreteColorKeyFrame KeyTime="0:0:2" Value="Black"/>
                <DiscreteColorKeyFrame KeyTime="0:0:3" Value="White"/>
                <DiscreteColorKeyFrame KeyTime="0:0:4" Value="Black"/>
            </ColorAnimationUsingKeyFrames.KeyFrames>
        </ColorAnimationUsingKeyFrames>
    </Storyboard>
</Window.Resources>

<Grid Name="grid" Background="Black">
    <TextBlock x:Name="TitleTextBlock" Text="{Binding TextTitle, NotifyOnTargetUpdated=True}" FontSize="32" HorizontalAlignment="Center" Grid.Row="0" FontFamily="OCR-A II" Foreground="White" VerticalAlignment="Bottom" Background="Black">
        <TextBlock.Triggers>
            <EventTrigger RoutedEvent="Binding.TargetUpdated">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <StaticResource ResourceKey="blinkAnimation"/>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
        </TextBlock.Triggers>    
    </TextBlock>
</Grid>

这将使 TextBlock 在每次文本更改时闪烁。请注意，在使用眨眼动画之前，必须在 TextBlock 上显式设置背景和前景，否则您将收到 System.InvalidOperationException: 'Background' property does not point to a DependencyObject in path '(0).(1)'.

更新

要从后面的代码启动此动画，您可以执行以下操作。

Storyboard blinkAnimation = TryFindResource("blinkAnimation") as Storyboard;
if (blinkAnimation != null)
{
    blinkAnimation.Begin();
}