LinearDoubleKeyFrame Class

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.Animation.DoubleKeyFrame
      System.Windows.Media.Animation.LinearDoubleKeyFrame

Syntax

'Declaration
Public NotInheritable Class LinearDoubleKeyFrame _
    Inherits DoubleKeyFrame

public sealed class LinearDoubleKeyFrame : DoubleKeyFrame

<LinearDoubleKeyFrame .../>

Constructors

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

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Properties

	Name	Description
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	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.)

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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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Remarks

This class is used as part of a DoubleKeyFrameCollection in conjunction with a DoubleAnimationUsingKeyFrames to animate a Double property value along a set of key frames.

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.

Linear key frames like LinearDoubleKeyFrame create a smooth, linear interpolation between values.

Examples

The following example moves a rectangle across a screen. The example uses the LinearDoubleKeyFrame 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.

Run this sample

' 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, EventArgs e)
{
    myStoryboard.Begin();
}

<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>

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.

See Also

Reference

Other Resources