FrameworkElement.BeginStoryboard Method (Storyboard, HandoffBehavior, Boolean)
Begins the sequence of actions contained in the provided storyboard, with specified state for control of the animation after it is started.
Assembly: PresentationFramework (in PresentationFramework.dll)
public void BeginStoryboard( Storyboard storyboard, HandoffBehavior handoffBehavior, bool isControllable )
- Type: System.Windows.Media.Animation.Storyboard
The storyboard to begin.
- Type: System.Windows.Media.Animation.HandoffBehavior
A value of the enumeration that describes behavior to use if a property described in the storyboard is already animated.
- Type: System.Boolean
Declares whether the animation is controllable (can be paused) after it is started.
Most typical animation scenarios do not use this method. Typically, you create the Storyboard or BeginStoryboard element in markup, and then you place these as the EventTrigger content on an element. When triggered by the event, the animation then runs. Most of the control aspects of a Storyboard can be addressed by properties that are exposed in markup.
For the signatures that do not use the isControllable, parameter, or when that parameter is specified false, the timeline clocks that are associated with the animation are removed as soon as the animation reaches the "Fill" period. Therefore the animation cannot be restarted after running once. Controlling an animation also requires that the storyboard have an x:Name Directive or be accessible by reference in code.
Handoff behavior can be specified as an attribute of BeginStoryboard.
Using the Compose HandoffBehavior
When you apply a Storyboard, AnimationTimeline, or AnimationClock to a property by using the Compose HandoffBehavior, any Clock objects previously associated with that property continue to consume system resources; the timing system does not remove the clocks automatically.
To avoid performance issues when you apply a large number of clocks by using Compose, you should remove composing clocks from the animated property after they complete. There are several ways to remove a clock:
To remove all clocks from a property, use the ApplyAnimationClock(DependencyProperty, AnimationClock) or BeginAnimation(DependencyProperty, AnimationTimeline) method of the animated object. Specify the property being animated as the first parameter, and null as the second. This removes all animation clocks from the property.
To remove a specific AnimationClock from a list of clocks, use the Controller property of the AnimationClock to retrieve a ClockController, then call the Remove method of the ClockController. This is typically done in the Completed event handler for a clock. Note that only root clocks can be controlled by a ClockController; the Controller property of a child clock returns null. Note also that the Completed event is not raised if the effective duration of the clock is forever. In that case, the user must determine when to call Remove.
This is primarily an issue for animations on objects that have a long lifetime. When an object is garbage collected, its clocks are also disconnected and garbage collected.
For more information about clock objects, see Animation and Timing System Overview.