DoubleAnimation Class

Definition

Namespace:

Windows.UI.Xaml.Media.Animation

Animates the value of a Double property between two target values using linear interpolation over a specified Duration.

public ref class DoubleAnimation sealed : Timeline

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
/// [Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
class DoubleAnimation final : Timeline

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
[Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
public sealed class DoubleAnimation : Timeline

Public NotInheritable Class DoubleAnimation
Inherits Timeline

<DoubleAnimation />

Inheritance

Object Platform::Object IInspectable DependencyObject Timeline DoubleAnimation

Attributes

ActivatableAttribute ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Windows requirements

Device family	Windows 10 (introduced in 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v1.0)

Examples

The following example shows how to use DoubleAnimation to create a rectangle that fades in and out of view after it is loaded.

<StackPanel>
    <StackPanel.Resources>
        <Storyboard x:Name="myStoryboard">
            <DoubleAnimation
          Storyboard.TargetName="MyAnimatedRectangle"
          Storyboard.TargetProperty="Opacity"
          From="1.0" To="0.0" Duration="0:0:3"
          AutoReverse="True" RepeatBehavior="Forever" />
        </Storyboard>
    </StackPanel.Resources>

    <Rectangle Loaded="Start_Animation" x:Name="MyAnimatedRectangle"
     Width="100" Height="100" Fill="Blue" />

</StackPanel>

// Start the animation when the object loads
private void Start_Animation(object sender, RoutedEventArgs e)
{
    myStoryboard.Begin();
}

' Start the animation when the object loads
Private Sub Start_Animation(ByVal sender As Object, ByVal e As EventArgs)
    myStoryboard.Begin()
End Sub

<Canvas>
    <Canvas.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>
    </Canvas.Resources>

    <Rectangle PointerPressed="Pointer_Clicked" Fill="Blue"
 Width="50" Height="50">
        <Rectangle.RenderTransform>
            <TranslateTransform x:Name="MyAnimatedTranslateTransform" />
        </Rectangle.RenderTransform>
    </Rectangle>

</Canvas>

// Start the animation when the object loads
private void Start_Animation(object sender, RoutedEventArgs e)
{
    myStoryboard.Begin();
}

' Start the animation when the object loads
Private Sub Start_Animation(ByVal sender As Object, ByVal e As EventArgs)
    myStoryboard.Begin()
End Sub

Remarks

Use DoubleAnimation to animate the property value of any dependency property that is of type Double.

Sometimes you'll need to use indirect property targeting in order to target a sub-property of another object that's the value of a property on the target. For example, in order to animate the X component of a RenderTransform of a UIElement, you need to reference some of the intermediate object-property values, until the last step in the indirect property path is truly a Double value, as is the case with TranslateTransform.X. The correct string to use for Storyboard.TargetProperty in this example is "(UIElement.RenderTransform).(TranslateTransform.X)". For more info on indirect property targeting and other storyboarded animation concepts, see Storyboarded animations.

A DoubleAnimation typically has at least one of the From, By or To properties set, but never all three.

• From only: The animation progresses from the value specified by the From property to the base value of the property being animated.
• From and To: The animation progresses from the value specified by the From property to the value specified by the To property.
• From and By: The animation progresses from the value specified by the From property to the value specified by the sum of the From and By properties.
• To only: The animation progresses from the animated property's base value or a previous animation's output value to the value specified by the To property.
• By only: The animation progresses from the base value of the property being animated or a previous animation's output value to the sum of that value and the value specified by the By property.

You can't animate the X and Y values of a Point using a DoubleAnimation, because these properties aren't dependency properties (Point is a structure and can't have dependency properties.) Instead, use PointAnimation to animate dependency properties that have a Point value.

You also can't use DoubleAnimation to animate int values or byte values. Instead, you'll have to use ObjectAnimationUsingKeyFrames, which won't give you an interpolation behavior, so you might need to define multiple keyframes to get a reasonably smooth animation. There aren't many UI-related dependency properties that use int values or byte values, so this shouldn't be a common scenario other than for custom properties.

The From, By or To properties of a DoubleAnimation aren't strictly a Double. Instead these are a Nullable for Double. The default value for these is null, not 0. That null value is how the animation system distinguishes that you haven't specifically set a value. Visual C++ component extensions (C++/CX) doesn't have a Nullable type, so it uses IReference instead.

Constructors

DoubleAnimation()

Initializes a new instance of the DoubleAnimation class.

Properties

AutoReverse	Gets or sets a value that indicates whether the timeline plays in reverse after it completes a forward iteration. (Inherited from Timeline)
BeginTime	Gets or sets the time at which this Timeline should begin. (Inherited from Timeline)
By	Gets or sets the total amount by which the animation changes its starting value.
ByProperty	Identifies the By  dependency property.
Dispatcher	Gets the CoreDispatcher that this object is associated with. The CoreDispatcher represents a facility that can access the DependencyObject on the UI thread even if the code is initiated by a non-UI thread. (Inherited from DependencyObject)
Duration	Gets or sets the length of time for which this timeline plays, not counting repetitions. (Inherited from Timeline)
EasingFunction	Gets or sets the easing function applied to this animation.
EasingFunctionProperty	Identifies the EasingFunction  dependency property.
EnableDependentAnimation	Gets or sets a value that declares whether animated properties that are considered dependent animations should be permitted to use this animation declaration.
EnableDependentAnimationProperty	Identifies the EnableDependentAnimation dependency property.
FillBehavior	Gets or sets a value that specifies how the animation behaves after it reaches the end of its active period. (Inherited from Timeline)
From	Gets or sets the animation's starting value.
FromProperty	Identifies the From  dependency property.
RepeatBehavior	Gets or sets the repeating behavior of this timeline. (Inherited from Timeline)
SpeedRatio	Gets or sets the rate, relative to its parent, at which time progresses for this Timeline. (Inherited from Timeline)
To	Gets or sets the animation's ending value.
ToProperty	Identifies the To  dependency property.

Methods

ClearValue(DependencyProperty)	Clears the local value of a dependency property. (Inherited from DependencyObject)
GetAnimationBaseValue(DependencyProperty)	Returns any base value established for a dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject)
GetValue(DependencyProperty)	Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject)
ReadLocalValue(DependencyProperty)	Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject)
RegisterPropertyChangedCallback(DependencyProperty, DependencyPropertyChangedCallback)	Registers a notification function for listening to changes to a specific DependencyProperty on this DependencyObject instance. (Inherited from DependencyObject)
SetValue(DependencyProperty, Object)	Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject)
UnregisterPropertyChangedCallback(DependencyProperty, Int64)	Cancels a change notification that was previously registered by calling RegisterPropertyChangedCallback. (Inherited from DependencyObject)

Events

Completed

Occurs when the Storyboard object has completed playing. (Inherited from Timeline)

See also

• Timeline
• DoubleAnimationUsingKeyFrames
• Storyboarded animations
• XAML animation sample
• Double
• Double