[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Represents an easing function that creates an animation that resembles a spring oscillating back and forth until it comes to rest.
Assembly: System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.
Thetype exposes the following members.
|Dispatcher||Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)|
|EasingMode||Gets or sets a value that specifies how the animation interpolates. (Inherited from EasingFunctionBase.)|
|Oscillations||Gets or sets the number of times the target slides back and forth over the animation destination.|
|Springiness||Gets or sets the stiffness of the spring. The smaller the Springiness value is, the stiffer the spring and the faster the elasticity decreases in intensity over each oscillation.|
|CheckAccess||Determines whether the calling thread has access to this object. (Inherited from DependencyObject.)|
|ClearValue||Clears the local value of a dependency property. (Inherited from DependencyObject.)|
|Ease||Transforms normalized time to control the pace of an animation. (Inherited from EasingFunctionBase.)|
|EaseInCore||Provides the logic portion of the easing function that you can override to produce the EaseIn mode of the custom easing function. (Overrides EasingFunctionBase.EaseInCore(Double).)|
|Equals(Object)||Determines whether the specified Object is equal to the current Object. (Inherited from Object.)|
|Finalize||Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)|
|GetAnimationBaseValue||Returns any base value established for a Windows Phone dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)|
|GetHashCode||Serves as a hash function for a particular type. (Inherited from Object.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|GetValue||Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|ReadLocalValue||Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)|
|SetValue||Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
You can control when in the "spring" behavior occurs in an animation by specifying the EasingMode property value. The following graph demonstrates the different values of EasingMode, where f(t) represents the animation progress and t represents time.
Because this animation causes values to oscillate back and forth, the animation might interpolate into negative numbers unexpectedly. This can cause errors when animating properties that do not allow negative numbers. For example, if you apply this animation to the Height of an object (e.g. from 0 to 200 with an EasingMode of EaseIn), the animation will attempt to interpolate through negative numbers for Height which will throw an error.
In addition to using the easing functions included in the run-time, you can create your own custom easing functions by inheriting from EasingFunctionBase.
The following example applies an easing function to a DoubleAnimation to create an animation that resembles a spring oscillating back and forth until it comes to rest.
<StackPanel x:Name="LayoutRoot" Background="Transparent"> <StackPanel.Resources> <Storyboard x:Name="myStoryboard"> <DoubleAnimation From="30" To="200" Duration="00:00:4" Storyboard.TargetName="myRectangle" Storyboard.TargetProperty="Height"> <DoubleAnimation.EasingFunction> <!-- Elastic easing function assigned to From/To animation --> <ElasticEase x:Name="myElasticEase" Oscillations="3" Springiness="1" EasingMode="EaseOut"/> </DoubleAnimation.EasingFunction> </DoubleAnimation> </Storyboard> </StackPanel.Resources> <Rectangle x:Name="myRectangle" MouseLeftButtonDown="Mouse_Clicked" Fill="Blue" Width="200" Height="30" /> </StackPanel>