Double​Animation​Using​Key​Frames Double​Animation​Using​Key​Frames Double​Animation​Using​Key​Frames Class

Definition

Animates the value of a Double property along a set of key frames.

public : sealed class DoubleAnimationUsingKeyFrames : Timeline, IDoubleAnimationUsingKeyFramespublic sealed class DoubleAnimationUsingKeyFrames : Timeline, IDoubleAnimationUsingKeyFramesPublic NotInheritable Class DoubleAnimationUsingKeyFrames Inherits Timeline Implements IDoubleAnimationUsingKeyFrames
<DoubleAnimationUsingKeyFrames>
  oneOrMoreDoubleKeyFrames
</DoubleAnimationUsingKeyFrames>
Inheritance
DoubleAnimationUsingKeyFramesDoubleAnimationUsingKeyFramesDoubleAnimationUsingKeyFrames
Attributes
Windows 10 requirements
Device family
Windows 10 (introduced v10.0.10240.0)
API contract
Windows.Foundation.UniversalApiContract (introduced v1)

Inherited Members

Inherited properties

Inherited methods

Inherited events

Examples

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:

  1. 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.
  2. 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.
  3. In the final two seconds, it uses an instance of the SplineDoubleKeyFrame class to move the rectangle back to its starting position. Spline key frames like SplineDoubleKeyFrame 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" EnableDependentAnimation="True">

                <!-- 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>
' Start the animation when the object loads
Private Sub Start_Animation(ByVal sender As Object, ByVal e As EventArgs)
    myStoryboard.Begin()
End Sub
// Start the animation when the object loads
private void Start_Animation(object sender, RoutedEventArgs e)
{
    myStoryboard.Begin();
}

Constructors

DoubleAnimationUsingKeyFrames() DoubleAnimationUsingKeyFrames() DoubleAnimationUsingKeyFrames()

Initializes a new instance of the DoubleAnimationUsingKeyFrames class.

public : DoubleAnimationUsingKeyFrames()public DoubleAnimationUsingKeyFrames()Public Sub New()
Attributes

Properties

EnableDependentAnimation EnableDependentAnimation EnableDependentAnimation

Gets or sets a value that declares whether animated properties that are considered dependent animations should be permitted to use this animation declaration.

public : PlatForm::Boolean EnableDependentAnimation { get; set; }public bool EnableDependentAnimation { get; set; }Public ReadWrite Property EnableDependentAnimation As bool
<DoubleAnimationUsingKeyFrames EnableDependentAnimation="bool" />
Value
PlatForm::Boolean bool bool

true if the animation can be used for a dependent animation case. false if the animation cannot be used for a dependent animation case. The default is false.

Attributes

Remarks

What's considered a dependent animation?

Not all custom animations you create can run by default in a Windows Runtime app, if the animation system determines that the animation might cause bad performance in your UI. Animations where the system determines there could be a performance impact are called dependent animations. It's dependent because your animation is actively and frequently updating objects on the UI thread, which is also where current user input and other programmatic updates are making runtime changes to UI.

A dependent animation that's consuming extensive system resources on the UI thread can make the app appear unresponsive in certain situations. If your animation causes a layout change or otherwise has the potential to impact performance on the UI thread, you often need to explicitly enable the animation to see it run. That's what the EnableDependentAnimation property on specific animation classes is for. Use this property with caution, because setting it to true means you are deliberately acknowledging that the animation might slow down other operations on the UI thread when it runs.

For more info, see Storyboarded animations. That topic includes a list of the criteria for an independent animation. An animation is a dependent animation if it doesn't satisfy at least one of those criteria. For the specific property you intend to animate, and for the specifics of your animation, compare your intended animation to the criteria to see whether it would be considered dependent or independent by the system.

Another way to discover whether your animations are dependent is that you might receive a warning from your XAML design surface or tool after you compose that animation, and the warning indicates that you'll need to set EnableDependentAnimation to true to see your animation run.

As an app developer, you can also choose to apply an app-wide setting that always disables dependent animations, even those where EnableDependentAnimation is true. See Timeline.AllowDependentAnimations. This is useful to you as an app developer if you're consuming controls where the templates have dependent animations, and you've identified that as a performance problem, but you don't want to have to retemplate the whole control to turn those animations off.

See Also

EnableDependentAnimationProperty EnableDependentAnimationProperty EnableDependentAnimationProperty

Identifies the EnableDependentAnimation dependency property.

public : static DependencyProperty EnableDependentAnimationProperty { get; }public static DependencyProperty EnableDependentAnimationProperty { get; }Public Static ReadOnly Property EnableDependentAnimationProperty As DependencyProperty
Value
DependencyProperty DependencyProperty DependencyProperty

The identifier for the EnableDependentAnimation dependency property.

Attributes

KeyFrames KeyFrames KeyFrames

Gets the collection of DoubleKeyFrame objects that define the animation.

public : DoubleKeyFrameCollection KeyFrames { get; }public DoubleKeyFrameCollection KeyFrames { get; }Public ReadOnly Property KeyFrames As DoubleKeyFrameCollection
<DoubleAnimationUsingKeyFrames>
  oneOrMoreDoubleKeyFrames
</DoubleAnimationUsingKeyFrames>
Value
DoubleKeyFrameCollection DoubleKeyFrameCollection DoubleKeyFrameCollection

The collection of DoubleKeyFrame objects that define the animation. The default is an empty collection.

Attributes

See Also