运行故事板如果属性满足条件

Question

我有一个 TextBlock 当用户将他的设置保存到数据库时它会动画。

但问题是，动画只需要在保存到数据库成功后运行。

如果保存成功：显示文本 Saved successfully 为白色文本并在几秒后淡出。

如果保存失败：显示文本 An error has occured 红色文本并且不淡出

目前我有这个 XAML 但这将始终动画：

我不知道如何有条件地制作 EventTrigger。任何帮助将不胜感激！

<TextBlock Text="{Binding Message, NotifyOnTargetUpdated=True}" TextAlignment="Center" Padding="5" Grid.Row="3" Grid.Column="3" VerticalAlignment="Top">
    <TextBlock.Style>
        <Style TargetType="{x:Type TextBlock}">
            <Setter Property="Foreground" Value="#FFE8E8E8"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding HasError}" Value="True">
                    <Setter Property="Foreground" Value="Red"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </TextBlock.Style>         
    <TextBlock.Triggers>
        <EventTrigger RoutedEvent="Binding.TargetUpdated">
            <BeginStoryboard>
                <Storyboard x:Name="sb">
                    <ObjectAnimationUsingKeyFrames BeginTime="0:0:0" Storyboard.TargetProperty="Visibility">
                        <DiscreteObjectKeyFrame KeyTime="0">
                            <DiscreteObjectKeyFrame.Value>
                                <Visibility>Visible</Visibility>
                            </DiscreteObjectKeyFrame.Value>
                        </DiscreteObjectKeyFrame>
                    </ObjectAnimationUsingKeyFrames>
                    <DoubleAnimation BeginTime="0:0:0.0" Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:0"/>
                    <DoubleAnimation BeginTime="0:0:5.0" Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="0:0:0.5"/>
                    <ObjectAnimationUsingKeyFrames BeginTime="0:0:5.5" Storyboard.TargetProperty="Visibility">
                        <DiscreteObjectKeyFrame KeyTime="0">
                            <DiscreteObjectKeyFrame.Value>
                                <Visibility>Hidden</Visibility>
                            </DiscreteObjectKeyFrame.Value>
                        </DiscreteObjectKeyFrame>
                    </ObjectAnimationUsingKeyFrames>
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </TextBlock.Triggers>
</TextBlock>

如果我必须在代码中这样做：

if ("Message property has been changed" && HasError == false)
    The save was a succes!
else if ("Message property has been changed" && HasError == true)
    The save was a failure!

Answer 1

尝试使用数据触发器而不是事件触发器，并在视图模型中绑定一个布尔值来指示保存是否成功。由于您的情节提要中没有任何绑定，因此数据触发器应该没问题。 https://msdn.microsoft.com/en-us/library/system.windows.datatrigger%28v=vs.110%29.aspx

Answer 2

感谢 mnistic 我现在可以使用了，这是我的最终代码：

<TextBlock.Style>
    <Style TargetType="{x:Type TextBlock}">
        <Setter Property="Foreground" Value="#FFE8E8E8"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding HasError}" Value="True">
                <Setter Property="Foreground" Value="Red"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding HasError}" Value="False">
                <Setter Property="Foreground" Value="#FFE8E8E8"/>
                <DataTrigger.EnterActions>
                    <BeginStoryboard x:Name="sb">
                        <Storyboard>
                            <ObjectAnimationUsingKeyFrames BeginTime="0:0:0" Storyboard.TargetProperty="Visibility">
                                <DiscreteObjectKeyFrame KeyTime="0">
                                    <DiscreteObjectKeyFrame.Value>
                                        <Visibility>Visible</Visibility>
                                    </DiscreteObjectKeyFrame.Value>
                                </DiscreteObjectKeyFrame>
                            </ObjectAnimationUsingKeyFrames>
                            <DoubleAnimation BeginTime="0:0:0.0" Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:0"/>
                            <DoubleAnimation BeginTime="0:0:5.0" Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="0:0:0.5"/>
                            <ObjectAnimationUsingKeyFrames BeginTime="0:0:5.5" Storyboard.TargetProperty="Visibility">
                                <DiscreteObjectKeyFrame KeyTime="0">
                                    <DiscreteObjectKeyFrame.Value>
                                        <Visibility>Hidden</Visibility>
                                    </DiscreteObjectKeyFrame.Value>
                                </DiscreteObjectKeyFrame>
                            </ObjectAnimationUsingKeyFrames>
                        </Storyboard>
                    </BeginStoryboard>
                </DataTrigger.EnterActions>
                <DataTrigger.ExitActions>
                    <RemoveStoryboard BeginStoryboardName="sb"/>
                </DataTrigger.ExitActions>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</TextBlock.Style>

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运行故事板如果属性满足条件