Animatable::ApplyAnimationClock Method (DependencyProperty, AnimationClock, HandoffBehavior)
Assembly: PresentationCore (in PresentationCore.dll)
public: virtual void ApplyAnimationClock( DependencyProperty^ dp, AnimationClock^ clock, HandoffBehavior handoffBehavior ) sealed
- Type: System.Windows::DependencyProperty
The property to animate.
- Type: System.Windows.Media.Animation::AnimationClock
The clock with which to animate the specified property. If handoffBehavior is SnapshotAndReplace and clock is nullptr, all animations will be removed from the specified property (but not stopped). If handoffBehavior is Compose and clock is nullptr, this method has no effect.
- Type: System.Windows.Media.Animation::HandoffBehavior
A value that specifies how the new animation should interact with any current animations already affecting the property value.
ImplementsIAnimatable::ApplyAnimationClock(DependencyProperty, AnimationClock, HandoffBehavior)
Note that using this method to remove clocks from a property does not stop those clocks.
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 will 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 will remove 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 will return nullptr. Note also that the Completed event will not be called if the effective duration of the clock is forever. In that case, the user will need to 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 will also be disconnected and garbage collected.
For more information about clock objects, see the Animation and Timing System Overview.
The following example shows how to apply animation clocks using different HandoffBehavior settings.