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DoubleAnimation.By Property

Gets or sets the total amount by which the animation changes its starting value. This is a dependency property.

Namespace: System.Windows.Media.Animation
Assembly: PresentationCore (in presentationcore.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

public Nullable<double> By { get; set; }
/** @property */
public Nullable<double> get_By ()

/** @property */
public void set_By (Nullable<double> value)

public function get By () : Nullable<double>

public function set By (value : Nullable<double>)

<object By="Double"/>- or -<object By="{x:Null}"/>

Property Value

The total amount by which the animation changes its starting value. The default value is null.

Identifier field

ByProperty

Metadata properties set to true

None

Use the By property when you want to animate a value "by" a certain amount, rather than specifying a starting or ending value. You may also use the By property with the From property.

The following table summarizes how the From, To, and By properties may be used together or separately to determine an animation's target values.

Properties specified

Resulting behavior

From

The animation progresses from the value specified by the From property to the base value of the property being animated or to a previous animation's output value, depending on how the previous animation is configured.

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

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

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.

NoteNote:

If you set both the To and By properties, the To property takes precedence and the By property is ignored.

To use other interpolation methods or animate between more than two target values, use a DoubleAnimationUsingKeyFrames object.

A "From/To/By" or "basic animation" creates a transition between two target values (see Animation Overview for an introduction to different types of animations). To set the target values of a basic animation, use its From, To, and By properties. The following table summarizes how the From, To, and By properties may be used together or separately to determine an animation's target values.

Properties specified

Resulting behavior

From

The animation progresses from the value specified by the From property to the base value of the property being animated or to a previous animation's output value, depending on how the previous animation is configured.

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

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

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.

NoteNote:

Do not set both the To property and the By property on the same animation.

To use other interpolation methods or animate between more than two target values, use a key frame animation. See KeyFrame Animations for more information.

For information about applying multiple animations to a single property, see KeyFrame Animations.

The example below shows the different effects of setting To, By, and From properties on animations.

<!-- This example shows the different effects of setting
   To, By, and From properties on animations.  -->
<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

  <StackPanel Margin="20">

    <!-- Demonstrates the From and To properties used together. -->
    <Rectangle Name="fromToAnimatedRectangle" Height="10" Width="100" 
      HorizontalAlignment="Left" Margin="10" Fill="#99FF9900" />

    <!-- Demonstrates the use of the To property. -->
    <Rectangle Name="toAnimatedRectangle" Height="10" Width="100" 
      HorizontalAlignment="Left" Margin="10" Fill="#99FF9900" />

    <!-- Demonstrates the use of the By property. -->
    <Rectangle Name="byAnimatedRectangle" Height="10" Width="100" 
      HorizontalAlignment="Left" Margin="10" Fill="#99FF9900" />

    <!-- Demonstrates the use of the From and By properties. -->
    <Rectangle Name="fromByAnimatedRectangle" Height="10" Width="100" 
      HorizontalAlignment="Left" Margin="10" Fill="#99FF9900" />

    <!-- Demonstrates the use of the From property. -->
    <Rectangle Name="fromAnimatedRectangle" Height="10" Width="100" 
      HorizontalAlignment="Left" Margin="10" Fill="#99FF9900" />
    <Button>
      Start Animations
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard FillBehavior="Stop">

              <!-- Demonstrates the From and To properties used together.
                 Animates the rectangle's Width property from 50 to 300 over 10 seconds. -->
              <DoubleAnimation 
                Storyboard.TargetName="fromToAnimatedRectangle" 
                Storyboard.TargetProperty="(Rectangle.Width)"
                From="50" To="300" Duration="0:0:10" />

              <!-- Demonstrates the To property used by itself.
                 Animates the Rectangle's Width property from its base value
                 (100) to 300 over 10 seconds. -->
              <DoubleAnimation 
                Storyboard.TargetName="toAnimatedRectangle" Storyboard.TargetProperty="(Rectangle.Width)"
                To="300" Duration="0:0:10" />

              <!-- Demonstrates the By property used by itself.
                 Increments the Rectangle's Width property by 300 over 10 seconds.
                 As a result, the Width property is animated from its base value
                 (100) to 400 (100 + 300) over 10 seconds. -->
              <DoubleAnimation 
                Storyboard.TargetName="byAnimatedRectangle" Storyboard.TargetProperty="(Rectangle.Width)" 
                By="300" Duration="0:0:10" />

              <!-- Demonstrates the From and By properties used together.
                 Increments the Rectangle's Width property by 300 over 10 seconds.
                 As a result, the Width property is animated from 50
                 to 350 (50 + 300) over 10 seconds. -->
              <DoubleAnimation 
                Storyboard.TargetName="fromByAnimatedRectangle" Storyboard.TargetProperty="(Rectangle.Width)" 
                From="50" By="300" Duration="0:0:10"  />

              <!-- Demonstrates the From property used by itself.
                 Animates the rectangle's Width property from 50 to its base value (100)
                 over 10 seconds. -->
              <DoubleAnimation 
                Storyboard.TargetName="fromAnimatedRectangle" Storyboard.TargetProperty="(Rectangle.Width)"
                From="50" Duration="0:0:10"  />
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Button.Triggers>
    </Button>
  </StackPanel>
</Page>

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0
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