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Animieren eines Doubles mithilfe von Keyframes

In diesem Beispiel wird veranschaulicht, wie Sie den Wert einer Eigenschaft, die ein Double annimmt, mithilfe von Keyframes animieren.

Beispiel

Im folgenden Beispiel wird ein Rechteck über einen Bildschirm verschoben. Im Beispiel wird die DoubleAnimationUsingKeyFrames-Klasse verwendet, um die X-Eigenschaft einer TranslateTransform-Klasse zu animieren, die auf ein Rectangle angewendet wird. Diese Animation, die unbegrenzt wiederholt wird, verwendet drei Keyframes auf folgende Weise:

  1. In den ersten drei Sekunden wird eine Instanz der LinearDoubleKeyFrame-Klasse verwendet, um das Rechteck mit konstanter Geschwindigkeit auf einem Pfad von der Startposition bis zur Position 500 zu bewegen. Lineare Keyframes wie LinearDoubleKeyFrame sorgen für einen reibungslosen linearen Übergang zwischen Werten.

  2. Am Ende der vierten Sekunde wird eine Instanz der DiscreteDoubleKeyFrame-Klasse verwendet, um das Rechteck sofort an die nächste Position zu bewegen. Diskrete Keyframes wie DiscreteDoubleKeyFrame verursachen plötzliche Sprünge zwischen den Werten. In diesem Beispiel befindet sich das Rechteck an der Anfangsposition und erscheint dann plötzlich bei Position 500.

  3. In den letzten zwei Sekunden wird eine Instanz der SplineDoubleKeyFrame-Klasse verwendet, um das Rechteck zurück an seine Ausgangsposition zu verschieben. Spline-Keyframes wie SplineDoubleKeyFrame erzeugen einen variablen Übergang zwischen den Werten entsprechend den Werten der KeySpline-Eigenschaft. In diesem Beispiel bewegt sich das Rechteck zunächst langsam und beschleunigt dann exponentiell im letzten Bereich des Zeitabschnitts.

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>

Das vollständige Beispiel finden Sie unter KeyFrame-Animationsbeispiel.

Aus Gründen der Konsistenz mit anderen Animationsbeispielen wird in den Codeversionen dieses Beispiels ein Storyboard-Objekt zum Anwenden der DoubleAnimationUsingKeyFrames verwendet. Alternativ ist es beim Anwenden einer einzelnen Animation im Code einfacher, die BeginAnimation-Methode zu verwenden, anstatt eine Storyboardzu verwenden. Ein Beispiel finden Sie unter Vorgehensweise: Animieren einer Eigenschaft ohne Storyboard.

Siehe auch

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