I wrote an
article on my Blog in which I describe a technique as a workaround on how to "add" additional events to a Silverlight 4 Storyboard. The Silverlight 4 Storyboard class only has one single event, which is the
Completed event. There a numerous needs to add additional events to a storyboard but because the Storyboard class is sealed this isn't possible. So we need a workaround which is provided by the
StoryboardEventHelper class. The StoryboardEventHeler class that is build step by step in the article implements two addititional events (OnStoryboardStarted and OnStoryboardPositionChanged) that provide for example the opportunity to easily change the VisualState of any Object at a certain timeline position of a running storyboard. In addition to the article you can
view a small sample app and download the full sourcecode at the Expression Gallery.
Have fun!