此示例演示如何使用关键帧来为具有 Double 值的属性设置动画。
例
以下示例在屏幕中移动一个矩形。 该示例使用 DoubleAnimationUsingKeyFrames 类对应用于 Rectangle的 TranslateTransform 的 X 属性进行动画处理。 此动画无限期重复，采用以下方式使用三个关键帧：
在前三秒内，使用 LinearDoubleKeyFrame 类的实例，以稳定的速率沿路径移动矩形，从起始位置移动到位置500。 线性关键帧（如 LinearDoubleKeyFrame）在值之间创建平滑线性转换。
在第四秒结束时，使用 DiscreteDoubleKeyFrame 类的一个实例，将矩形迅速移动到下一个位置。 离散关键帧（如 DiscreteDoubleKeyFrame）会在数值之间产生突然的跳变。 在此示例中，矩形位于起始位置，然后突然出现在 500 位置。
在最后两秒内，使用 SplineDoubleKeyFrame 类的实例将矩形移回其起始位置。 SplineDoubleKeyFrame 之类的自由绘制曲线关键帧根据 KeySpline 属性的值在值之间创建变量过渡。 在此示例中，矩形首先缓慢移动，然后以指数方式加速到时间段的末尾。
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Media;
namespace Microsoft.Samples.KeyFrameExamples
{
/// <summary>
/// This example shows how to use the DoubleAnimationUsingKeyFrames class to
/// animate the position of an object.
/// Key frame animations enable you to create complex animations
/// by specifying multiple destination values
/// and controlling the animation's interpolation method.
/// </summary>
public class AltDoubleAnimationUsingKeyFramesExample : Page
{
public AltDoubleAnimationUsingKeyFramesExample()
{
Title = "DoubleAnimationUsingKeyFrames Example";
Background = Brushes.White;
Margin = new Thickness(20);
// Create a NameScope for this page so that
// Storyboards can be used.
NameScope.SetNameScope(this, new NameScope());
// Create a rectangle.
Rectangle aRectangle = new Rectangle();
aRectangle.Width = 100;
aRectangle.Height = 100;
aRectangle.Stroke = Brushes.Black;
aRectangle.StrokeThickness = 5;
// Create a Canvas to contain and
// position the rectangle.
Canvas containerCanvas = new Canvas();
containerCanvas.Width = 610;
containerCanvas.Height = 300;
containerCanvas.Children.Add(aRectangle);
Canvas.SetTop(aRectangle, 100);
Canvas.SetLeft(aRectangle, 10);
// Create a TranslateTransform to
// move the rectangle.
TranslateTransform animatedTranslateTransform =
new TranslateTransform();
aRectangle.RenderTransform = animatedTranslateTransform;
// Assign the TranslateTransform a name so that
// it can be targeted by a Storyboard.
this.RegisterName(
"AnimatedTranslateTransform", animatedTranslateTransform);
// Create a DoubleAnimationUsingKeyFrames to
// animate the TranslateTransform.
DoubleAnimationUsingKeyFrames translationAnimation
= new DoubleAnimationUsingKeyFrames();
translationAnimation.Duration = TimeSpan.FromSeconds(6);
// Animate from the starting position to 500
// over the first second using linear
// interpolation.
translationAnimation.KeyFrames.Add(
new LinearDoubleKeyFrame(
500, // Target value (KeyValue)
KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3))) // KeyTime
);
// Animate from 500 (the value of the previous key frame)
// to 400 at 4 seconds using discrete interpolation.
// Because the interpolation is discrete, the rectangle will appear
// to "jump" from 500 to 400.
translationAnimation.KeyFrames.Add(
new DiscreteDoubleKeyFrame(
400, // Target value (KeyValue)
KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4))) // KeyTime
);
// Animate from 400 (the value of the previous key frame) to 0
// over two seconds, starting at 4 seconds (the key time of the
// last key frame) and ending at 6 seconds.
translationAnimation.KeyFrames.Add(
new SplineDoubleKeyFrame(
0, // Target value (KeyValue)
KeyTime.FromTimeSpan(TimeSpan.FromSeconds(6)), // KeyTime
new KeySpline(0.6,0.0,0.9,0.0) // KeySpline
)
);
// Set the animation to repeat forever.
translationAnimation.RepeatBehavior = RepeatBehavior.Forever;
// Set the animation to target the X property
// of the object named "AnimatedTranslateTransform."
Storyboard.SetTargetName(translationAnimation, "AnimatedTranslateTransform");
Storyboard.SetTargetProperty(
translationAnimation, new PropertyPath(TranslateTransform.XProperty));
// Create a storyboard to apply the animation.
Storyboard translationStoryboard = new Storyboard();
translationStoryboard.Children.Add(translationAnimation);
// Start the storyboard after the rectangle loads.
aRectangle.Loaded += delegate(object sender, RoutedEventArgs e)
{
translationStoryboard.Begin(this);
};
Content = containerCanvas;
}
}
}
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Shapes
Imports System.Windows.Media.Animation
Imports System.Windows.Media
Namespace Microsoft.Samples.KeyFrameExamples
''' <summary>
''' This example shows how to use the DoubleAnimationUsingKeyFrames class to
''' animate the position of an object.
''' Key frame animations enable you to create complex animations
''' by specifying multiple destination values
''' and controlling the animation's interpolation method.
''' </summary>
Public Class AltDoubleAnimationUsingKeyFramesExample
Inherits Page
Public Sub New()
Title = "DoubleAnimationUsingKeyFrames Example"
Background = Brushes.White
Margin = New Thickness(20)
' Create a NameScope for this page so that
' Storyboards can be used.
NameScope.SetNameScope(Me, New NameScope())
' Create a rectangle.
Dim aRectangle As New Rectangle()
aRectangle.Width = 100
aRectangle.Height = 100
aRectangle.Stroke = Brushes.Black
aRectangle.StrokeThickness = 5
' Create a Canvas to contain and
' position the rectangle.
Dim containerCanvas As New Canvas()
containerCanvas.Width = 610
containerCanvas.Height = 300
containerCanvas.Children.Add(aRectangle)
Canvas.SetTop(aRectangle, 100)
Canvas.SetLeft(aRectangle, 10)
' Create a TranslateTransform to
' move the rectangle.
Dim animatedTranslateTransform As New TranslateTransform()
aRectangle.RenderTransform = animatedTranslateTransform
' Assign the TranslateTransform a name so that
' it can be targeted by a Storyboard.
Me.RegisterName("AnimatedTranslateTransform", animatedTranslateTransform)
' Create a DoubleAnimationUsingKeyFrames to
' animate the TranslateTransform.
Dim translationAnimation As New DoubleAnimationUsingKeyFrames()
translationAnimation.Duration = TimeSpan.FromSeconds(6)
' Animate from the starting position to 500
' over the first second using linear
' interpolation.
translationAnimation.KeyFrames.Add(New LinearDoubleKeyFrame(500, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3)))) ' KeyTime - Target value (KeyValue)
' Animate from 500 (the value of the previous key frame)
' to 400 at 4 seconds using discrete interpolation.
' Because the interpolation is discrete, the rectangle will appear
' to "jump" from 500 to 400.
translationAnimation.KeyFrames.Add(New DiscreteDoubleKeyFrame(400, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4)))) ' KeyTime - Target value (KeyValue)
' Animate from 400 (the value of the previous key frame) to 0
' over two seconds, starting at 4 seconds (the key time of the
' last key frame) and ending at 6 seconds.
translationAnimation.KeyFrames.Add(New SplineDoubleKeyFrame(0, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(6)), New KeySpline(0.6,0.0,0.9,0.0))) ' KeySpline - KeyTime - Target value (KeyValue)
' Set the animation to repeat forever.
translationAnimation.RepeatBehavior = RepeatBehavior.Forever
' Set the animation to target the X property
' of the object named "AnimatedTranslateTransform."
Storyboard.SetTargetName(translationAnimation, "AnimatedTranslateTransform")
Storyboard.SetTargetProperty(translationAnimation, New PropertyPath(TranslateTransform.XProperty))
' Create a storyboard to apply the animation.
Dim translationStoryboard As New Storyboard()
translationStoryboard.Children.Add(translationAnimation)
' Start the storyboard after the rectangle loads.
AddHandler aRectangle.Loaded, Sub(sender As Object, e As RoutedEventArgs) translationStoryboard.Begin(Me)
Content = containerCanvas
End Sub
End Class
End Namespace
<!-- This example shows how to use the DoubleAnimationUsingKeyFrames to
animate the position of an object.
Key frame animations enable you to create complex animations
by specifying multiple destination values
and controlling the animation's interpolation method.
-->
<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="DoubleAnimationUsingKeyFrames Example"
Background="White" Margin="20">
<Canvas Width="610" Height="300">
<!-- The position of this rectangle is animated using
a key frame animation. -->
<Rectangle
Canvas.Top="100"
Canvas.Left="10"
Height="100"
Width="100"
Stroke="Black"
StrokeThickness="5">
<Rectangle.RenderTransform>
<TranslateTransform x:Name="AnimatedTranslateTransform" />
</Rectangle.RenderTransform>
<Rectangle.Triggers>
<EventTrigger RoutedEvent="Rectangle.Loaded">
<BeginStoryboard>
<Storyboard>
<!-- Animate the TranslateTransform.X property using 3 KeyFrames
which animates the rectangle along a straight line.
This animation repeats indefinitely. -->
<DoubleAnimationUsingKeyFrames
Storyboard.TargetName="AnimatedTranslateTransform"
Storyboard.TargetProperty="X"
Duration="0:0:6"
RepeatBehavior="Forever">
<!-- 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>
</BeginStoryboard>
</EventTrigger>
</Rectangle.Triggers>
</Rectangle>
</Canvas>
</Page>
有关完整示例，请参阅 关键帧动画示例。
为了与其他动画示例保持一致，此示例的代码版本使用 Storyboard 对象来应用 DoubleAnimationUsingKeyFrames。 或者，在代码中应用单个动画时，使用 BeginAnimation 方法而不是使用 Storyboard更简单。 有关示例，请参阅在不使用情节提要的情况下对属性进行动画处理。
