Question

All,

Can someone tell me why this KeyTime is telling me it is a negative value at runtime? I’ve removed some logic that builds a path to an image.

public Storyboard CreateAnimationStoryBoard(DependencyObject dependencyObjectTarget,Image targetImage)
{
        try
        {



            Storyboard sb = new Storyboard();
            Storyboard.SetTarget(sb, dependencyObjectTarget);
            Storyboard.SetTargetName(sb, targetImage.Name);
            Storyboard.SetTargetProperty(sb, new PropertyPath(Image.SourceProperty));

            ObjectAnimationUsingKeyFrames oaukf = new ObjectAnimationUsingKeyFrames();

            oaukf.Duration = TimeSpan.FromSeconds(animationLength);
            oaukf.BeginTime = new TimeSpan(0, 0, 0);

            for (int i = startFrame; i <= endFrame; i++)
            {
                *build an animation string path here (hidden)*

                Uri u;

                Uri.TryCreate(animationString.ToString(), UriKind.RelativeOrAbsolute, out u);
                BitmapImage bi = new BitmapImage(u);

                DiscreteObjectKeyFrame dokf = new DiscreteObjectKeyFrame();

                dokf.KeyTime = KeyTime.Uniform;
                dokf.Value = bi;

                oaukf.KeyFrames.Add(dokf);

            }

            sb.Children.Add(oaukf);
            return sb;

        }

Now, specifically, at runtime, it tells me that “KeyTime property on KeyFrame object must be set to a non-negative TimeSpan value”. If I dive a bit deeper in the variable, I get no further debugging information. I’ve checked if the bitmaps are null, which they aren’t. I’ve tried setting my own timespan (to 1 second) for example, and I get the same error as above.

This all stems from a similar function I have in WPF that builds a storyboard in this exact manner. The only difference in the two is that the Keytime is set to KeyTime.PACED in wpf. Since Silverlight apparently doesn’t have this option, I used Uniform and have run into this error. Can someone shed some light on why this is happening in Silverlight, but works completely fine in WPF?

Answer 1

Your use of the Keytime variable is a bit off:

In setting your keyframe, say on Visibility, use this:

        DiscreteObjectKeyFrame kf = new DiscreteObjectKeyFrame();
        kf.KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(1000));
        kf.Value = Visibility.Visible;