Assembly: System.Windows (in System.Windows.dll)
Thetype exposes the following members.
|Dispatcher||Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)|
|KeySpline||Gets or sets the two control points that define animation progress for this key frame.|
|KeyTime||Gets or sets the time at which the key frame's target Value should be reached. (Inherited from DoubleKeyFrame.)|
|Value||Gets or sets the key frame's target value. (Inherited from DoubleKeyFrame.)|
|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.)|
|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 Silverlight 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.)|
A key frame defines a segment of the DoubleAnimationUsingKeyFrames to which it belongs. Each key frame has a target Value and a KeyTime. The KeyTime specifies the time at which the key frame's Value should be reached. A key frame animates from the target value of the previous key frame to its own target value. It starts when the previous key frame ends and ends when its own key time is reached.
Spline key frames like create a variable transition between values that is determined by the KeySpline property. Splined interpolation can be used to achieve more realistic "real world" timing effects such as acceleration and deceleration.
A cubic Bezier curve is defined by a start point, an end point, and two control points. The KeySpline property of a spline key frame defines the two control points of a Bezier curve that extends from (0,0) to (1,1). The first control point controls the curve factor of the first half of the Bezier curve, and the second control point controls the curve factor of the second half of the Bezier segment. The resulting curve describes the rate of change for that spline key frame. The steeper the curve, the faster the key frame changes its values. As the curve gets flatter, the key frame changes its values more slowly.
Run the sample below to see how changing the KeySpline value effects the interpolation of the animation. Also, this sample demonstrates the effect of the KeySpline on the Bezier curve which represents the interpolation.
The following example moves a rectangle across a screen. The example uses the DoubleAnimationUsingKeyFrames class to animate the X property of a TranslateTransform applied to a Rectangle. This animation uses three key frames in the following manner:
During the first three seconds, it uses an instance of the LinearDoubleKeyFrame class to move the rectangle along a path at a steady rate from its starting position to the 500 position. Linear key frames like LinearDoubleKeyFrame create a smooth linear transition between values.
At the end of the fourth second, it uses an instance of the DiscreteDoubleKeyFrame class to suddenly move the rectangle to the next position. Discrete key frames like DiscreteDoubleKeyFrame create sudden jumps between values. In this example, the rectangle is at the starting position and then suddenly appears at the 500 position.
In the final two seconds, it uses an instance of the class to move the rectangle back to its starting position. Spline key frames such as create a variable transition between values according to the value of the KeySpline property. In this example, the rectangle begins by moving slowly and then speeds up exponentially toward the end of the time segment.
<StackPanel> <StackPanel.Resources> <Storyboard x:Name="myStoryboard"> <!-- Animate the TranslateTransform's X property from 0 to 350, then 50, then 200 over 10 seconds. --> <DoubleAnimationUsingKeyFrames Storyboard.TargetName="MyAnimatedTranslateTransform" Storyboard.TargetProperty="X" Duration="0:0:10"> <!-- Using a LinearDoubleKeyFrame, the rectangle moves steadily from its starting position to 500 over the first 3 seconds. --> <LinearDoubleKeyFrame Value="500" KeyTime="0:0:3" /> <!-- Using a DiscreteDoubleKeyFrame, the rectangle suddenly appears at 400 after the fourth second of the animation. --> <DiscreteDoubleKeyFrame Value="400" KeyTime="0:0:4" /> <!-- Using a SplineDoubleKeyFrame, the rectangle moves back to its starting point. The animation starts out slowly at first and then speeds up. This KeyFrame ends after the 6th second. --> <SplineDoubleKeyFrame KeySpline="0.6,0.0 0.9,0.00" Value="0" KeyTime="0:0:6" /> </DoubleAnimationUsingKeyFrames> </Storyboard> </StackPanel.Resources> <Rectangle Fill="Blue" Width="50" Height="50" Loaded="Start_Animation"> <Rectangle.RenderTransform> <TranslateTransform x:Name="MyAnimatedTranslateTransform" X="0" Y="0" /> </Rectangle.RenderTransform> </Rectangle> </StackPanel>
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.