Animate a StatusBarItem when its DataContext changes

Question

I would like to animate a StatusBarItem whenever its text is updated, the VisualState is fine and plays if for instance I trigger it during a MouseEnter event; however I can't get it to play during DataContextChanged event.

<Window.Resources>
    <Color x:Key="ColorRed">Red</Color>
</Window.Resources>

<VisualStateManager.VisualStateGroups>
    <VisualStateGroup x:Name="VisualStateGroup">
        <VisualState x:Name="Animate">
            <Storyboard AutoReverse="True">
                <ColorAnimationUsingKeyFrames Storyboard.TargetName="StatusBarItem1" Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">
                    <EasingColorKeyFrame KeyTime="0:0:0.2" Value="{StaticResource ColorRed}" />
                </ColorAnimationUsingKeyFrames>
            </Storyboard>
        </VisualState>
    </VisualStateGroup>
</VisualStateManager.VisualStateGroups>

<StatusBarItem x:Name="StatusBarItem1" Content="{Binding TargetNullValue='Placeholder'}">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="DataContextChanged">
            <ei:GoToStateAction StateName="Animate" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
</StatusBarItem>

This is how I update the DataContext :

...
catch (Exception ex)
{
    var s = string.Format("Building preview for asset failed: {0}", ex.Message);
    StatusBarItem1.DataContext = s;
}

If I listen to the event it is indeed called :

StatusBarItem1.DataContextChanged += StatusBarItem1_DataContextChanged;
void StatusBarItem1_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
{
}

How can I trigger the animation whenever the StatusBarItem text changes ?

Answer 1

See this solution, which indicates that this needs to be done on the code-behind and can't be done in pure XAML. The problem isn't exactly the same, but the same solution should work for you by manually starting the animation.