WPF MVVM - Trigger storyboard on property change only happens once - wpf

Question

In my view model, I have a timer that needs to make a border background blink every 5 minutes.
The border in my view:
<Border Name="btnBorder" Grid.Row="0" Grid.Column="0" Opacity="1" CornerRadius="10,10,0,0">
<Border.Style>
<Style TargetType="Border">
<Style.Setters>
<Setter Property="Background" Value="#e2e2e2"></Setter>
</Style.Setters>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=ViewEventTrigger}" Value="True">
<DataTrigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)">
<EasingColorKeyFrame KeyTime="00:00:00.000" Value="#e2e2e2"/>
<EasingColorKeyFrame KeyTime="00:00:00.500" Value="#163f6b"/>
<EasingColorKeyFrame KeyTime="00:00:01.000" Value="#e2e2e2"/>
<EasingColorKeyFrame KeyTime="00:00:01.500" Value="#163f6b"/>
<EasingColorKeyFrame KeyTime="00:00:02.000" Value="#e2e2e2"/>
<EasingColorKeyFrame KeyTime="00:00:02.500" Value="#163f6b"/>
<EasingColorKeyFrame KeyTime="00:00:03.000" Value="#e2e2e2"/>
<EasingColorKeyFrame KeyTime="00:00:03.500" Value="#163f6b"/>
<EasingColorKeyFrame KeyTime="00:00:04.000" Value="#e2e2e2"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</DataTrigger.EnterActions>
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
</Border>
Property from view model:
private string _viewEventTrigger = "";
public string ViewEventTrigger
{
get => _viewEventTrigger ?? (_viewEventTrigger = "");
private set
{
if (_viewEventTrigger == value)
return;
_viewEventTrigger = value;
OnPropertyChanged();
}
}
And the method that needs to trigger the... well, trigger:
private void ShowInfocenterIfAnyItinirary(object sender, ElapsedEventArgs e)
{
ViewEventTrigger = "";
ViewEventTrigger = "True";
}
I testet the Storyboard by triggering it with MouseEnter. But I am not able to make it work by binding it to my property.
EDIT:
I set the datacontext like this:
d:DataContext="{d:DesignInstance local:ItineraryViewModel}"
Also, I have lots og other databindings that work fine, like data to show and commands for buttons. But I just can't make the trigger execute the storybord.
The method ShowInfocenterIfAnyItinirary() is executed by a timer, started in the viewmodel.
Timer code:
private readonly Timer _timer = new Timer();
public ItineraryViewModel()
{
_timer.Interval = 5000;
_timer.Elapsed += ShowInfocenterIfAnyItinirary;
_timer.Start();
}
EDIT 2:
I have delayed when the animation should start when the program runs. I have discovered that the animation DOES run, but only once. I did not see it before, because the window starts minimized.
Why does it only run once, no matter how many times the trigger event happens?

Answer 1

This only sets the design time data context:
d:DataContext="{d:DesignInstance local:ItineraryViewModel}"
This won't have any effect when you actualy run the application.
You should set the DataContext property of the view to an instance of your view model:
<Window ...>
<Window.DataContext>
<local:ItineraryViewModel />
</Window.DataContext>

Answer 2

I ended up solving the problem like this:
private void ShowInfocenterIfAnyItinirary(object sender, ElapsedEventArgs e)
{
if (Items.Count <= 0) return;
GlobalEvents.TriggerShowMainWindowEvent();
ViewEventTrigger = "True";
Task.Run(async () =>
{
Thread.Sleep(4000);
ViewEventTrigger = "False";
});
}
This stops the animation, instead of leaving it paused at the end point.