private static void OnTransitionPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var source = (TransitioningContentControl)d;
var oldTransition = (TransitionType)e.OldValue;
var newTransition = (TransitionType)e.NewValue;
if (source.IsTransitioning)
{
source.AbortTransition();
}
// find new transition
Storyboard newStoryboard = source.GetStoryboard(newTransition);
// unable to find the transition.
if (newStoryboard == null)
{
// could be during initialization of xaml that presentationgroups was not yet defined
if (VisualStates.TryGetVisualStateGroup(source, PresentationGroup) == null)
{
// will delay check
source.CurrentTransition = null;
}
else
{
// revert to old value
source.SetValue(TransitionProperty, oldTransition);
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "Temporary removed exception message", newTransition));
}
}
else
{
source.CurrentTransition = newStoryboard;
}
}