Storyboard.GetCurrentProgress Method (FrameworkElement)
Assembly: PresentationFramework (in PresentationFramework.dll)
Return ValueType: System.Nullable<Double>
null if this clock is Stopped, or 0.0 if this clock is active and its Timeline has a Duration of Forever; otherwise, a value between 0.0 and 1.0 that indicates the current progress of this clock within its current iteration. A value of 0.0 indicates no progress, and a value of 1.0 indicates that the clock is at the end of its current iteration.
To use this method to retrieve information about a storyboard's clock, the storyboard must be controllable. To make a storyboard controllable in code, you must use the appropriate overload of the storyboard's Begin method and specify true to make it controllable. For an example, see How to: Control a Storyboard After It Starts.