Storyboard::Begin Method (FrameworkElement, HandoffBehavior, Boolean)
Applies the animations associated with this Storyboard to their targets and initiates them.
Assembly: PresentationFramework (in PresentationFramework.dll)
public: void Begin( FrameworkElement^ containingObject, HandoffBehavior handoffBehavior, bool isControllable )
- Type: System.Windows::FrameworkElement
An object contained within the same name scope as the targets of this storyboard's animations. Animations without a specified TargetName are applied to containingObject.
- Type: System.Windows.Media.Animation::HandoffBehavior
The behavior the new animation should use to interact with any current animations.
- Type: System::Boolean
Declares whether the animation is controllable (can be paused) once started.
To interactively control this storyboard, you must use the same containingObject parameter when calling the interactive methods that you used to begin the storyboard
When this method is called, Clock objects are created for the storyboard and any timelines it contains. These clocks are stored with containingObject.
Using the Compose HandoffBehavior
When you apply a Storyboard, AnimationTimeline, or AnimationClock to a property using the Compose HandoffBehavior, any Clock objects previously associated with that property continue to consume system resources; the timing system does not remove these clocks automatically.
To avoid performance issues when you apply a large number of clocks 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 nullptr 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 nullptr. Note also that the Completed event is not called 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.
The following example shows how to create a controllable storyboard.