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11/18/2011

ColorAnimationUsingKeyFrames Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Animates the value of a Color property along a set of KeyFrames over a specified Duration.

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.Animation.Timeline
      System.Windows.Media.Animation.ColorAnimationUsingKeyFrames

Namespace: System.Windows.Media.Animation
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
<ContentPropertyAttribute("KeyFrames", True)> _
Public NotInheritable Class ColorAnimationUsingKeyFrames _
    Inherits Timeline

[ContentPropertyAttribute("KeyFrames", true)]
public sealed class ColorAnimationUsingKeyFrames : Timeline

<ColorAnimationUsingKeyFrames ...>
  oneOrMoreColorKeyFrames
</ColorAnimationUsingKeyFrames>

XAML Values

oneOrMoreColorKeyFrames
One or more object elements that define the key frames for the animation. These object elements represent one of the classes deriving from ColorKeyFrame. These are typically any combination of LinearColorKeyFrame, DiscreteColorKeyFrame, EasingColorKeyFrame, and SplineColorKeyFrame. Object elements defined here become members of the ColorKeyFrameCollection collection when code accesses the KeyFrames property at run time.

The ColorAnimationUsingKeyFrames type exposes the following members.

Constructors

	Name	Description
	ColorAnimationUsingKeyFrames	Initializes a new instance of the ColorAnimationUsingKeyFrames class.

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Properties

	Name	Description
	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.)
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	Duration	Gets or sets the length of time for which this timeline plays, not counting repetitions. (Inherited from Timeline.)
	FillBehavior	Gets or sets a value that specifies how the animation behaves after it reaches the end of its active period. (Inherited from Timeline.)
	KeyFrames	Gets the collection of ColorKeyFrame objects that define the animation.
	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.)

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Methods

	Name	Description
	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.)

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Events

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

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Remarks

A key frame animation's target values are defined by its KeyFrames property, which contains a collection of ColorKeyFrame objects. Each ColorKeyFrame defines a segment of the animation with its own target Value and KeyTime. When the animation runs, it progresses from one key value to the next at the specified key times.

There are three types of ColorKeyFrame classes, one for each supported interpolation method: LinearColorKeyFrame, DiscreteColorKeyFrame, and SplineColorKeyFrame.

Unlike a ColorAnimation, a ColorAnimationUsingKeyFrames can have more than two target values. You can also control the interpolation method of individual ColorKeyFrame segments.

When declaring a ColorAnimationUsingKeyFrames in XAML, the order of the ColorKeyFrame object elements is not significant, because the KeyTime controls the timing and therefore the order in which the key frames are executed. However, it is good markup style to keep the element order the same as the KeyTime sequence order.

Examples

The following example uses the ColorAnimationUsingKeyFrames class to animate the Background property of a StackPanel. This animation uses three key frames in the following manner:

During the first two seconds, LinearColorKeyFrame gradually changes the color from green to red. Linear key frames like LinearColorKeyFrame create a smooth linear transition between values.
During the end of the next half second, DiscreteColorKeyFrame quickly changes the color from red to yellow. Discrete key frames like DiscreteColorKeyFrame create sudden changes between values; the animation occurs quickly and has no interpolation between values at all.
During the final two seconds, SplineColorKeyFrame changes the color again, this time from yellow back to green. Spline key frames like SplineColorKeyFrame create a variable transition between values according to the values of the KeySpline property. A KeySpline provides a way to alter the relationship of time versus value during the animation duration to be nonlinear, and in particular the relationship can be a curve that would be difficult to produce with individual key frames. In this example, the change in color begins slowly and speeds up exponentially toward the end of the time segment.

Run this sample

<StackPanel Background="White" x:Name="myStackPanel"
            Loaded="Start_Animation">
    <StackPanel.Resources>
        <Storyboard x:Name="colorStoryboard">
            <ColorAnimationUsingKeyFrames BeginTime="00:00:00" 
             Storyboard.TargetName="myStackPanel" 
             Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">

                <!-- Go from green to red in the first 2 seconds. LinearColorKeyFrame creates
        a smooth, linear animation between values. -->
                <LinearColorKeyFrame Value="Red" KeyTime="00:00:02" />

                <!-- In the next half second, go to yellow. DiscreteColorKeyFrame creates a 
        sudden jump between values. -->
                <DiscreteColorKeyFrame Value="Yellow" KeyTime="00:00:2.5" />

                <!-- In the final 2 seconds of the animation, go from yellow back to green. SplineColorKeyFrame 
        creates a variable transition between values depending on the KeySpline property. In this example,
        the animation starts off slow but toward the end of the time segment, it speeds up exponentially.-->
                <SplineColorKeyFrame Value="Green" KeyTime="00:00:4.5" KeySpline="0.6,0.0 0.9,0.00" />

            </ColorAnimationUsingKeyFrames>
        </Storyboard>
    </StackPanel.Resources>
</StackPanel>

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

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

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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