Článek
11/18/2011

ObjectAnimationUsingKeyFrames Class

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

Animates the value of an Object 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.ObjectAnimationUsingKeyFrames

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

Syntax

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

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

<ObjectAnimationUsingKeyFrames>
  oneOrMoreDiscreteObjectKeyFrames
</ObjectAnimationUsingKeyFrames>

XAML Values

oneOrMoreDiscreteObjectKeyFrames
One or more DiscreteObjectKeyFrame object elements that define the key frames for the animation.

The ObjectAnimationUsingKeyFrames type exposes the following members.

Constructors

	Name	Description
	ObjectAnimationUsingKeyFrames	Initializes a new instance of the ObjectAnimationUsingKeyFrames 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 ObjectKeyFrame 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

Note:
Only discrete interpolation (DiscreteObjectKeyFrame) is available for use with ObjectAnimationUsingKeyFrames, which swaps object values according to a specified timeline. Other types of interpolation are too problematic to apply to objects.

Examples

The following example uses the ObjectAnimationUsingKeyFrames class to animate the Fill property of a Rectangle. This animation uses two key frames in the following manner:

Using a DiscreteObjectKeyFrame, the Fill property of the Rectangle suddenly changes to a LinearGradientBrush after the first two seconds of the animation.
After the third second of the animation, the Fill property is suddenly changed to a different LinearGradientBrush, which remains until the end of the animation (4 seconds total).

Run this sample

<StackPanel>
    <StackPanel.Resources>
        <Storyboard x:Name="myStoryboard">

            <!-- ObjectAnimationUsingKeyFrames is used to animate properties that take
         an object as a value. This animation lasts for 4 seconds using 3 KeyFrames which
         swap different brush objects at regular intervals, making the background of the Page
         change. -->
            <ObjectAnimationUsingKeyFrames
         Storyboard.TargetName="animatedRectangle"
         Storyboard.TargetProperty="Fill"
         Duration="0:0:4" RepeatBehavior="Forever">
                <ObjectAnimationUsingKeyFrames.KeyFrames>

                    <!-- Note: Only discrete interpolation (DiscreteObjectKeyFrame) is available for 
                use with ObjectAnimationUsingKeyFrames which merely swaps objects according to
                a specified timeline. Other types of interpolation are too problematic to apply
                to objects.  -->
                    <!-- Using a DiscreteObjectKeyFrame, the Fill property of the Rectangle suddenly  
                changes to a LinearGradientBrush after the first two seconds of the animation. -->
                    <DiscreteObjectKeyFrame KeyTime="0:0:2">
                        <DiscreteObjectKeyFrame.Value>
                            <LinearGradientBrush>
                                <LinearGradientBrush.GradientStops>
                                    <GradientStop Color="Yellow" Offset="0.0" />
                                    <GradientStop Color="Orange" Offset="0.5" />
                                    <GradientStop Color="Red" Offset="1.0" />
                                </LinearGradientBrush.GradientStops>
                            </LinearGradientBrush>
                        </DiscreteObjectKeyFrame.Value>
                    </DiscreteObjectKeyFrame>

                    <!-- After the third second of the animation, the Fill property is suddenly changed 
                to a different LinearGradientBrush which remains until the end of the animation 
                (4 seconds total). -->
                    <DiscreteObjectKeyFrame KeyTime="0:0:3">
                        <DiscreteObjectKeyFrame.Value>
                            <RadialGradientBrush GradientOrigin="0.75,0.25">
                                <RadialGradientBrush.GradientStops>
                                    <GradientStop Color="White" Offset="0.0" />
                                    <GradientStop Color="MediumBlue" Offset="0.5" />
                                    <GradientStop Color="Black" Offset="1.0" />
                                </RadialGradientBrush.GradientStops>
                            </RadialGradientBrush>
                        </DiscreteObjectKeyFrame.Value>
                    </DiscreteObjectKeyFrame>

                </ObjectAnimationUsingKeyFrames.KeyFrames>
            </ObjectAnimationUsingKeyFrames>
        </Storyboard>
    </StackPanel.Resources>

    <!-- The Fill property of this rectangle is animated. -->
    <Rectangle x:Name="animatedRectangle" Loaded="Rectangle_Loaded" Width="300" Height="300" />

</StackPanel>

' When the rectangle loads, begin the animation.
Private Sub Rectangle_Loaded(ByVal sender As Object, ByVal e As EventArgs)
    myStoryboard.Begin()
End Sub

// When the rectangle loads, begin the animation.
private void Rectangle_Loaded(object sender, EventArgs e)
{
    myStoryboard.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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