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RectAnimation.By Property

Gets or sets the total amount by which the animation changes its starting value.

Namespace:  System.Windows.Media.Animation
Assembly:  PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
public Nullable<Rect> By { get; set; }
<object>  <object.By>    <Rect />  </object.By></object>
<object By="Rect"/>- or -<object By="{x:Null Markup Extension}"/>

Property Value

Type: System.Nullable<Rect>
The total amount by which the animation changes its starting value. The default 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 RectAnimationUsingKeyFrames object.

This example shows how to animate changes to the size and position of a rectangle.

The following example uses an instance of the RectAnimation class to animate the Rect property of a RectangleGeometry, which animates changes to the size and position of the rectangle.

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Media;

namespace SDKSamples
{
    public class RectAnimationExample : Page
    {
        public RectAnimationExample()
        {

            // Create a NameScope for this page so that 
            // Storyboards can be used.
            NameScope.SetNameScope(this, new NameScope());

            RectangleGeometry myRectangleGeometry = new RectangleGeometry();
            myRectangleGeometry.Rect = new Rect(0, 200, 100, 100);

            // Assign the geometry a name so that 
            // it can be targeted by a Storyboard. 
            this.RegisterName(
                "MyAnimatedRectangleGeometry", myRectangleGeometry);

            Path myPath = new Path();
            myPath.Fill = Brushes.LemonChiffon;
            myPath.StrokeThickness = 1;
            myPath.Stroke = Brushes.Black;
            myPath.Data = myRectangleGeometry;

            RectAnimation myRectAnimation = new RectAnimation();
            myRectAnimation.Duration = TimeSpan.FromSeconds(2);
            myRectAnimation.FillBehavior = FillBehavior.HoldEnd;

            // Set the animation to repeat forever. 
            myRectAnimation.RepeatBehavior = RepeatBehavior.Forever;

            // Set the From and To properties of the animation.
            myRectAnimation.From = new Rect(0, 200, 100, 100);
            myRectAnimation.To = new Rect(600, 50, 200, 50);

            // Set the animation to target the Rect property 
            // of the object named "MyAnimatedRectangleGeometry."
            Storyboard.SetTargetName(myRectAnimation, "MyAnimatedRectangleGeometry");
            Storyboard.SetTargetProperty(
                myRectAnimation, new PropertyPath(RectangleGeometry.RectProperty));

            // Create a storyboard to apply the animation.
            Storyboard ellipseStoryboard = new Storyboard();
            ellipseStoryboard.Children.Add(myRectAnimation);

            // Start the storyboard when the Path loads.
            myPath.Loaded += delegate(object sender, RoutedEventArgs e)
            {
                ellipseStoryboard.Begin(this);
            };

            Canvas containerCanvas = new Canvas();
            containerCanvas.Children.Add(myPath);

            Content = containerCanvas;
        }
    }
}
<Page  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
  <StackPanel Orientation="Vertical" HorizontalAlignment="Center">
    <Path Stroke="Black" StrokeThickness="1" Fill="LemonChiffon">
      <Path.Data>
        <RectangleGeometry x:Name="myRectangleGeometry" Rect="0,200,100,100" />
      </Path.Data>
      <Path.Triggers>
        <EventTrigger RoutedEvent="Path.Loaded">
          <BeginStoryboard>
            <Storyboard>

              <!-- Animate the Rect property of the RectangleGeometry which causes the
              rectangle to animate postion and size. -->
              <RectAnimation
              Storyboard.TargetName="myRectangleGeometry"
              Storyboard.TargetProperty ="Rect"
              Duration="0:0:2" FillBehavior="HoldEnd" From="0,200,100,100" To="600,50,200,50" />
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Path.Triggers>
    </Path>
  </StackPanel>
</Page>

More Code

How to: Control an Animation using From, To, and ByA "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.

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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