From/To/By 动画概述

项目
08/12/2011

本主题描述如何使用 From/To/By 动画对依赖项属性进行动画处理。 From/To/By 动画创建两个值之间的过渡。

本主题包括以下部分。

先决条件

若要了解本主题，您应当熟悉 WPF 动画功能。有关动画功能的简介，请参见动画概述。

什么是 From/To/By 动画

From/To/By 动画是一种 AnimationTimeline 类型，它创建起始值和结束值之间的过渡。完成过渡所需的时间由该动画的 Duration 确定。

可以通过在标记和代码中使用 Storyboard，或在代码中使用 BeginAnimation 方法，将 From/To/By 动画应用于属性。还可以使用 From/To/By 动画创建 AnimationClock，并将其应用于一个或多个属性。有关应用动画的各种方法的更多信息，请参见属性动画技术概述。

From/To/By 动画的目标值不能超过两个。如果需要具有两个以上目标值的动画，请使用关键帧动画。关键帧动画概述中描述了关键帧动画。

From/To/By 动画类型

由于动画可生成属性值，因此对于不同的属性类型，会有不同的动画类型。若要对采用 Double 的属性（例如元素的 Width 属性）进行动画处理，请使用生成 Double 值的动画。若要对采用 Point 的属性进行动画处理，请使用生成 Point 值的动画，依此类推。

From/To/By 动画类属于 System.Windows.Media.Animation 命名空间，并使用下列命名约定：

*<类型>*Animation

其中，<类型> 是该类进行动画处理的值的类型。

WPF 提供下列 From/To/By 动画类。

属性类型	对应的 From/To/By 动画类
Byte	ByteAnimation
Color	ColorAnimation
Decimal	DecimalAnimation
Double	DoubleAnimation
Int16	Int16Animation
Int32	Int32Animation
Int64	Int64Animation
Point	PointAnimation
Quaternion	QuaternionAnimation
Rect	RectAnimation
Rotation3D	Rotation3DAnimation
Single	SingleAnimation
Size	SizeAnimation
Thickness	ThicknessAnimation
Vector3D	Vector3DAnimation
Vector	VectorAnimation

目标值

From/To/By 动画创建两个目标值之间的过渡。通常是指定一个起始值（使用 From 属性来设置）和一个结束值（使用 To 属性来设置）。但是，也可以只指定起始值、目标值或偏移量值。此时，动画从正在进行动画处理的属性获取缺少的目标值。以下列表描述了指定动画目标值的各种方法。

起始值

如果要显式指定动画的起始值，请使用 From 属性。可以只使用 From 属性自身，也可以将该属性与 To 或 By 属性一起使用。如果只指定 From 属性，则动画从该值过渡到进行动画处理的属性的基值。
结束值

若要指定动画的结束值，请使用其 To 属性。如果只使用 To 属性自身，则动画从正在进行动画处理的属性获取其起始值，或者从应用于同一属性的另一个动画的输出获取其起始值。可以将 To 属性与 From 属性一起使用，以显式指定动画的起始值和结束值。
偏移量值

可以使用 By 属性指定动画的偏移量，而不指定显式起始值或结束值。动画的 By 属性指定动画在其持续期间更改某值的程度。可以只使用 By 属性自身，也可以将该属性与 From 属性一起使用。如果只指定 By 属性，则动画将偏移量值添加到该属性的基值或另一个动画的输出。

使用 From/To/By 值

下面的部分介绍如何一起或单独使用 From、To 和 By 属性。

本部分中的每个示例都使用 DoubleAnimation（From/To/By 动画的一种类型）对一个高度为 10 个与设备无关的像素、宽度为 100 个与设备无关的像素的 Rectangle 的 Width 属性进行动画处理。

虽然每个示例都使用 DoubleAnimation，但所有 From/To/By 动画的 From、To 和 By 属性的行为都相同。虽然每个示例都使用 Storyboard，不过也可以通过其他方式使用 From/To/By 动画。有关更多信息，请参见属性动画技术概述。

From/To

如果同时设置了 From 和 To 值，则动画从 From 属性指定的值继续到 To 属性指定的值。

下面的示例将 DoubleAnimation 的 From属性设置为 50，并将其 To 属性设置为 300。结果，Rectangle 的 Width 以动画形式从 50 过渡到 300。

            ' Demonstrates the From and To properties used together.

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myRectangle As New Rectangle()

            ' Assign the Rectangle a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("fromToAnimatedRectangle", myRectangle)
            myRectangle.Height = 10
            myRectangle.Width = 100
            myRectangle.HorizontalAlignment = HorizontalAlignment.Left
            myRectangle.Fill = Brushes.Black

            ' Demonstrates the From and To properties used together.
            ' Animates the rectangle's Width property from 50 to 300 over 10 seconds.
            Dim myDoubleAnimation As New DoubleAnimation()
            myDoubleAnimation.From = 50
            myDoubleAnimation.To = 300
            myDoubleAnimation.Duration = New Duration(TimeSpan.FromSeconds(10))

            Storyboard.SetTargetName(myDoubleAnimation, "fromToAnimatedRectangle")
            Storyboard.SetTargetProperty(myDoubleAnimation, New PropertyPath(Rectangle.WidthProperty))
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(myDoubleAnimation)

            ' Use an anonymous event handler to begin the animation
            ' when the rectangle is clicked.
            AddHandler myRectangle.MouseLeftButtonDown, Sub(sender As Object, args As MouseButtonEventArgs) myStoryboard.Begin(myRectangle)

// Demonstrates the From and To properties used together.

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

Rectangle myRectangle = new Rectangle();

// Assign the Rectangle a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
    "fromToAnimatedRectangle", myRectangle);
myRectangle.Height = 10;
myRectangle.Width = 100;
myRectangle.HorizontalAlignment = HorizontalAlignment.Left;
myRectangle.Fill = Brushes.Black;

// Demonstrates the From and To properties used together.
// Animates the rectangle's Width property from 50 to 300 over 10 seconds.
DoubleAnimation myDoubleAnimation = new DoubleAnimation();
myDoubleAnimation.From = 50;
myDoubleAnimation.To = 300;
myDoubleAnimation.Duration =
    new Duration(TimeSpan.FromSeconds(10));

Storyboard.SetTargetName(myDoubleAnimation, "fromToAnimatedRectangle");
Storyboard.SetTargetProperty(myDoubleAnimation,
    new PropertyPath(Rectangle.WidthProperty));
Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(myDoubleAnimation);

// Use an anonymous event handler to begin the animation
// when the rectangle is clicked.
myRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs args)
    {
        myStoryboard.Begin(myRectangle);

    };

<!-- Demonstrates the From and To properties used together. -->
<Rectangle Name="fromToAnimatedRectangle"
   Height="10" Width="100" HorizontalAlignment="Left"
   Fill="Black">
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
      <BeginStoryboard>
        <Storyboard>
        <!-- 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="Width"
          From="50" To="300" Duration="0:0:10" />
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

若要

如果只设置 To 属性，则动画从进行动画处理的属性的基值，或以前应用于同一属性的组合动画的输出，继续到 To 属性指定的值。

（“组合动画”是指以前应用于同一属性、在使用 Compose 提交行为应用当前动画时仍然有效的 Active 或 Filling 动画）。

下面的示例只将 DoubleAnimation 的 To 属性设置为 300。由于未指定起始值，因此 DoubleAnimation 使用 Width 属性的基值 (100) 作为其起始值。 Rectangle 的 Width 以动画形式从 100 过渡到动画的目标值 300。

            ' Demonstrates the use of the To property.

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myRectangle As New Rectangle()

            ' Assign the Rectangle a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("toAnimatedRectangle", myRectangle)
            myRectangle.Height = 10
            myRectangle.Width = 100
            myRectangle.HorizontalAlignment = HorizontalAlignment.Left
            myRectangle.Fill = Brushes.Gray

            ' Demonstrates the To property used by itself. Animates
            ' the Rectangle's Width property from its base value
            ' (100) to 300 over 10 seconds.
            Dim myDoubleAnimation As New DoubleAnimation()
            myDoubleAnimation.To = 300
            myDoubleAnimation.Duration = New Duration(TimeSpan.FromSeconds(10))

            Storyboard.SetTargetName(myDoubleAnimation, "toAnimatedRectangle")
            Storyboard.SetTargetProperty(myDoubleAnimation, New PropertyPath(Rectangle.WidthProperty))
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(myDoubleAnimation)

            ' Use an anonymous event handler to begin the animation
            ' when the rectangle is clicked.
            AddHandler myRectangle.MouseLeftButtonDown, Sub(sender As Object, args As MouseButtonEventArgs) myStoryboard.Begin(myRectangle)

// Demonstrates the use of the To property.

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

Rectangle myRectangle = new Rectangle();

// Assign the Rectangle a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
    "toAnimatedRectangle", myRectangle);
myRectangle.Height = 10;
myRectangle.Width = 100;
myRectangle.HorizontalAlignment = HorizontalAlignment.Left;
myRectangle.Fill = Brushes.Gray;

// Demonstrates the To property used by itself. Animates
// the Rectangle's Width property from its base value
// (100) to 300 over 10 seconds.
DoubleAnimation myDoubleAnimation = new DoubleAnimation();
myDoubleAnimation.To = 300;
myDoubleAnimation.Duration =
    new Duration(TimeSpan.FromSeconds(10));

Storyboard.SetTargetName(myDoubleAnimation, "toAnimatedRectangle");
Storyboard.SetTargetProperty(myDoubleAnimation,
    new PropertyPath(Rectangle.WidthProperty));
Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(myDoubleAnimation);

// Use an anonymous event handler to begin the animation
// when the rectangle is clicked.
myRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs args)
    {
        myStoryboard.Begin(myRectangle);

    };

<!-- Demonstrates the use of the To property. -->
<Rectangle Name="toAnimatedRectangle"
   Height="10" Width="100" HorizontalAlignment="Left"
   Fill="Gray">
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
      <BeginStoryboard>
        <Storyboard>

          <!-- 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="Width"
            To="300" Duration="0:0:10" />
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

By

如果只设置动画的 By 属性，则动画从正在进行动画处理的属性的基值，或组合动画的输出，继续到该值与 By 属性指定的值之和。

下面的示例只将 DoubleAnimation 的 By 属性设置为 300。由于该示例未指定起始值，因此 DoubleAnimation 使用 Width 属性的基值 100 作为其起始值。结束值通过将动画的 By 值 300 与其起始值 100 相加而得到 400。因此，Rectangle 的 Width 以动画形式从 100 过渡到 400。

            ' Demonstrates the use of the By property.

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myRectangle As New Rectangle()

            ' Assign the Rectangle a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("byAnimatedRectangle", myRectangle)
            myRectangle.Height = 10
            myRectangle.Width = 100
            myRectangle.HorizontalAlignment = HorizontalAlignment.Left
            myRectangle.Fill = Brushes.RoyalBlue

            ' 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.
            Dim myDoubleAnimation As New DoubleAnimation()
            myDoubleAnimation.By = 300
            myDoubleAnimation.Duration = New Duration(TimeSpan.FromSeconds(10))

            Storyboard.SetTargetName(myDoubleAnimation, "byAnimatedRectangle")
            Storyboard.SetTargetProperty(myDoubleAnimation, New PropertyPath(Rectangle.WidthProperty))
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(myDoubleAnimation)

            ' Use an anonymous event handler to begin the animation
            ' when the rectangle is clicked.
            AddHandler myRectangle.MouseLeftButtonDown, Sub(sender As Object, args As MouseButtonEventArgs) myStoryboard.Begin(myRectangle)

// Demonstrates the use of the By property.

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

Rectangle myRectangle = new Rectangle();

// Assign the Rectangle a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
    "byAnimatedRectangle", myRectangle);
myRectangle.Height = 10;
myRectangle.Width = 100;
myRectangle.HorizontalAlignment = HorizontalAlignment.Left;
myRectangle.Fill = Brushes.RoyalBlue;

// 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 myDoubleAnimation = new DoubleAnimation();
myDoubleAnimation.By = 300;
myDoubleAnimation.Duration =
    new Duration(TimeSpan.FromSeconds(10));

Storyboard.SetTargetName(myDoubleAnimation, "byAnimatedRectangle");
Storyboard.SetTargetProperty(myDoubleAnimation,
    new PropertyPath(Rectangle.WidthProperty));
Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(myDoubleAnimation);

// Use an anonymous event handler to begin the animation
// when the rectangle is clicked.
myRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs args)
    {
        myStoryboard.Begin(myRectangle);

    };

<!-- Demonstrates the use of the By property. -->
<Rectangle Name="byAnimatedRectangle" 
   Height="10" Width="100" HorizontalAlignment="Left"
   Fill="RoyalBlue">
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
      <BeginStoryboard>
        <Storyboard>

          <!-- 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="Width" 
            By="300" Duration="0:0:10" />
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

From/By

如果设置了动画的 From 和 By 属性，则动画从 From 属性指定的值，继续到由 From 和 By 属性之和指定的值。

下面的示例将 DoubleAnimation 的 From属性设置为 50，并将其 By 属性设置为 300。结束值通过将动画的 By 值 300 与其起始值 50 相加而得到 350。因此，Rectangle 的 Width 以动画形式从 50 过渡到 350。

            ' Demonstrates the use of the From and By properties.

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myRectangle As New Rectangle()

            ' Assign the Rectangle a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("byAnimatedRectangle", myRectangle)
            myRectangle.Height = 10
            myRectangle.Width = 100
            myRectangle.HorizontalAlignment = HorizontalAlignment.Left
            myRectangle.Fill = Brushes.BlueViolet

            ' 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.
            Dim myDoubleAnimation As New DoubleAnimation()
            myDoubleAnimation.From = 50
            myDoubleAnimation.By = 300
            myDoubleAnimation.Duration = New Duration(TimeSpan.FromSeconds(10))

            Storyboard.SetTargetName(myDoubleAnimation, "byAnimatedRectangle")
            Storyboard.SetTargetProperty(myDoubleAnimation, New PropertyPath(Rectangle.WidthProperty))
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(myDoubleAnimation)

            ' Use an anonymous event handler to begin the animation
            ' when the rectangle is clicked.
            AddHandler myRectangle.MouseLeftButtonDown, Sub(sender As Object, args As MouseButtonEventArgs) myStoryboard.Begin(myRectangle)

// Demonstrates the use of the From and By properties.

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

Rectangle myRectangle = new Rectangle();

// Assign the Rectangle a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
    "byAnimatedRectangle", myRectangle);
myRectangle.Height = 10;
myRectangle.Width = 100;
myRectangle.HorizontalAlignment = HorizontalAlignment.Left;
myRectangle.Fill = Brushes.BlueViolet;

// 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 myDoubleAnimation = new DoubleAnimation();
myDoubleAnimation.From = 50;
myDoubleAnimation.By = 300;
myDoubleAnimation.Duration =
    new Duration(TimeSpan.FromSeconds(10));

Storyboard.SetTargetName(myDoubleAnimation, "byAnimatedRectangle");
Storyboard.SetTargetProperty(myDoubleAnimation,
    new PropertyPath(Rectangle.WidthProperty));
Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(myDoubleAnimation);

// Use an anonymous event handler to begin the animation
// when the rectangle is clicked.
myRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs args)
    {
        myStoryboard.Begin(myRectangle);
    };

<!-- Demonstrates the use of the From and By properties. -->
<Rectangle Name="fromByAnimatedRectangle" Grid.Row="6" Grid.Column="2"
   Height="10" Width="100" HorizontalAlignment="Left"
   Fill="BlueViolet">
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
      <BeginStoryboard>
        <Storyboard>

          <!-- Demonstrates the From and By properties used by 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="Width" 
            From="50" By="300" Duration="0:0:10"  />

        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

发件人

如果只指定动画的 From 值，则动画从 From 属性指定的值，继续到正在进行动画处理的属性的基值，或组合动画的输出。

下面的示例只将 DoubleAnimation 的 From 属性设置为 50。由于未指定结束值，因此 DoubleAnimation 使用 Width 属性的基值 100 作为其结束值。 Rectangle 的 Width 以动画形式从 50 过渡到 Width 属性的基值 100。

            ' Demonstrates the use of the From property.

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myRectangle As New Rectangle()

            ' Assign the Rectangle a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("fromAnimatedRectangle", myRectangle)
            myRectangle.Height = 10
            myRectangle.Width = 100
            myRectangle.HorizontalAlignment = HorizontalAlignment.Left
            myRectangle.Fill = Brushes.Purple

            ' Demonstrates the From property used by itself. Animates the
            ' rectangle's Width property from 50 to its base value (100)
            ' over 10 seconds.
            Dim myDoubleAnimation As New DoubleAnimation()
            myDoubleAnimation.From = 50
            myDoubleAnimation.Duration = New Duration(TimeSpan.FromSeconds(10))

            Storyboard.SetTargetName(myDoubleAnimation, "fromAnimatedRectangle")
            Storyboard.SetTargetProperty(myDoubleAnimation, New PropertyPath(Rectangle.WidthProperty))
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(myDoubleAnimation)

            ' Use an anonymous event handler to begin the animation
            ' when the rectangle is clicked.
            AddHandler myRectangle.MouseLeftButtonDown, Sub(sender As Object, args As MouseButtonEventArgs) myStoryboard.Begin(myRectangle)

// Demonstrates the use of the From property.

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

Rectangle myRectangle = new Rectangle();

// Assign the Rectangle a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
    "fromAnimatedRectangle", myRectangle);
myRectangle.Height = 10;
myRectangle.Width = 100;
myRectangle.HorizontalAlignment = HorizontalAlignment.Left;
myRectangle.Fill = Brushes.Purple;

// Demonstrates the From property used by itself. Animates the
// rectangle's Width property from 50 to its base value (100)
// over 10 seconds.
DoubleAnimation myDoubleAnimation = new DoubleAnimation();
myDoubleAnimation.From = 50;
myDoubleAnimation.Duration =
    new Duration(TimeSpan.FromSeconds(10));

Storyboard.SetTargetName(myDoubleAnimation, "fromAnimatedRectangle");
Storyboard.SetTargetProperty(myDoubleAnimation,
    new PropertyPath(Rectangle.WidthProperty));
Storyboard myStoryboard = new Storyboard();
myStoryboard.Children.Add(myDoubleAnimation);

// Use an anonymous event handler to begin the animation
// when the rectangle is clicked.
myRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs args)
    {
        myStoryboard.Begin(myRectangle);
    };

<!-- Demonstrates the use of the From property. -->
<Rectangle Name="fromAnimatedRectangle" Grid.Row="8" Grid.Column="2"
   Height="10" Width="100" HorizontalAlignment="Left" 
   Fill="Purple">
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
      <BeginStoryboard>
        <Storyboard>
          <!-- 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="Width"
            From="50" Duration="0:0:10"  />
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

To/By

如果同时设置了动画的 To 和 By 属性，则忽略 By 属性。

其他动画类型

From/To/By 动画不是 WPF 提供的唯一动画类型，它还提供了关键帧动画和路径动画。

关键帧动画沿着用关键帧所描述的任意数量的目标值进行动画处理。有关更多信息，请参见关键帧动画概述。
路径动画从 PathGeometry 生成输出值。有关更多信息，请参见路径动画概述。

WPF 还允许您创建自己的自定义动画类型。有关更多信息，请参见自定义动画概述。

请参见

通过