Why does my Storyboard only run once?

Question

I have a storyboard that I would like to run multiple times. Unfortunately, after it runs the first time, even when this code is hit, it doesn't animate again. It only animates the first time. I'm setting an initial value....even when I set the value before I run it again.

DoubleAnimationUsingKeyFrames animateTransformX = new DoubleAnimationUsingKeyFrames();

EasingDoubleKeyFrame initialTransformXKeyframe = new EasingDoubleKeyFrame();
initialTransformXKeyframe.KeyTime = TimeSpan.FromSeconds(0);
//Resetting the value before running it again.
initialTransformXKeyframe.Value = 0;
animateTransformX.KeyFrames.Add(initialTransformXKeyframe);


EasingDoubleKeyFrame animateTransformXKeyframe = new EasingDoubleKeyFrame();
animateTransformXKeyframe.KeyTime = TimeSpan.FromSeconds(0.5);
animateTransformXKeyframe.Value = aDynamicValueGoesHere; 
animateTransformX.KeyFrames.Add(animateTransformXKeyframe);


Storyboard.SetTarget(animateTransformX, image);
Storyboard.SetTargetProperty(animateTransformX, new PropertyPath("(UIElement.RenderTransform).(TransformGroup.Children)[0].(TranslateTransform.X)"));

Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(animateTransformX);

myStoryboard.Begin(this);

I feel like it is very simple but for the life of me I can't understand why. Any help would be appreciated.

EDIT

The reason I was doing it from codebehind is because storyboards are freezable and I have had trouble in the past with dynamic values in them. For simplicity I didn't put that I was using a dynamic value in the code; I updated the code above to show I'm using a dynamic value.

I tried adding the storyboard as XAML inside a resource with the use of a dynamic value. It works fine (and replays) if a non-dynamic value is used but it only plays once (the first time) when a dynamic value is used.

So, if {Binding OffsetX} were replaced with 50, for example, this works fine, and repeatedly.OffsetX gets updated through a property that implements INotifyPropertyChanged. Even if it were the same, if it were never updated, I would think it should still animate, just to the same value it animated to before (like it does with 50). But that isn't the case; it just doesn't animate again. So now I'm really lost.

<Storyboard x:Key="InitialAnimate">
    <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(TranslateTransform.X)" Storyboard.TargetName="StoryImage">
        <EasingDoubleKeyFrame KeyTime="0:0:0.6" Value="{Binding OffsetX}"/>
    </DoubleAnimationUsingKeyFrames>
</Storyboard>

EDIT 2

I didn't fix the problem but I found a workaround that works for my particular situation. I was getting this error in my output window:

System.Windows.Media.Animation Warning: 6 : Unable to perform action because the specified Storyboard was never applied to this object for interactive control.; Action='Stop'; Storyboard='System.Windows.Media.Animation.Storyboard'; Storyboard.HashCode='28715394'; Storyboard.Type='System.Windows.Media.Animation.Storyboard'; TargetElement='System.Windows.Controls.Grid'; TargetElement.HashCode='6255521'; TargetElement.Type='System.Windows.Controls.Grid'

I found a few StackOverflow answers regarding it, including how to find what Storyboard caused the issue and another unanswered question.

I am still not sure how to fix my original issue, but here's my workaround. Since I only needed the animation to run when you restarted (an event that happens in my viewmodel), I use an event raised in the viewmodel and consumed in the parent view to remove and then re-add the UserControl that contains the animation.

In that UserControl, I trigger the storyboard through a ControlStoryboardAction tied to a Loaded EventTrigger. This makes the animation run when it loads, and it only ever runs the animation once during the life of the UserControl. I am able to use the dynamic values in XAML. Here's how I'm removing and readding the view from it's parent:

Parent View:

<grid x:Name="imageHolder></grid>

Parent Codebehind:

private void CreateAnimations(object sender, EventArgs e)
{
    imageHolder.Children.RemoveAt(0);
    Views.Image image = new Image();
    image.Name = "image";
    imageHolder.Children.Add(image);
}

+1 Your code looks right... Does it work correctly if you create the animation in XAML instead? — BradleyDotNET, Mar 05 '14 at 23:16
This works correctly in XAML, but I am using dynamic properties and it is within an ItemsControl. I'll edit my question to give a little more information. — jporcenaluk, Mar 06 '14 at 20:58
It even works with dynamic properties...but only the first time, just like it does in the codebehind. I'm using a value that is updated through `INotifyPropertyChanged`. — jporcenaluk, Mar 06 '14 at 21:59
Does it still not loop if you add the 0 KeyTime to some initial value that is never equal to OffsetX? — BradleyDotNET, Mar 06 '14 at 22:18
I did not try that, but I did find a workaround that works for my particular situation. — jporcenaluk, Mar 07 '14 at 22:07

score 0 · Answer 1 · edited May 23 '17 at 11:57

0

You can't change the Value property at runtime the way you're doing after the edit.

This is because Animations are freezable objects. There is more information in the MSDN Documentation, but basically it means you can't use binding because properties in the frozen object (i.e. the animation) cannot change.

To get around this limitation, you will need to do some or all of the work in code-behind.

See Why Storyboard value wouldn't get from a resource or binding?

So You probably want to go back to the codebehind method.

So as a final answer, what I would do is when I want to run it again:

Remove the previous storyboard
create a whole brand new Storyboard(or just the animation) and run that.

edited May 23 '17 at 11:57

Community

1
1

answered Mar 07 '14 at 16:34

Kelly Elton

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My goal is to repeat every once in a while, not continuously forever. I tried find the storyboard after it has been created, stopping it on completed, and then beginning it again after...no such luck. – jporcenaluk Mar 07 '14 at 21:51
Oh in that case...If you're doing it by code anyways, just do raw animations and skip storyboards all together. They're a bit easier to manage. – Kelly Elton Mar 07 '14 at 21:53
That...is a great idea. I found a workaround but I will try it out to help out future code explorers. – jporcenaluk Mar 07 '14 at 22:09

Why does my Storyboard only run once?

1 Answers1