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ClockController.SpeedRatio Property

Gets or sets the interactive speed of the target Clock.

Namespace:  System.Windows.Media.Animation
Assembly:  PresentationCore (in PresentationCore.dll)

public double SpeedRatio { get; set; }

Property Value

Type: System.Double
A finite value greater than zero that describes the interactive speed of the target clock. This value is multiplied against the value of the SpeedRatio of the clock's Timeline. For example, if the timeline's SpeedRatio is 0.5 and the ClockController object's SpeedRatio is 3.0, the timeline moves at 1.5 times normal speed (0.5 * 3.0). The default value is 1.0.

Setting this property has no effect until the next tick. If you set this property and then get its value before the next tick occurs, you'll get the old value. This property will return the new value after the next tick.

Setting this property does not change the value of the underlying timeline's SpeedRatio.

Setting this property triggers the target clock's CurrentGlobalSpeedInvalidated event.

A ClockController object's SpeedRatio property enables you to change the speed of a Clock without altering the SpeedRatio of the clock's Timeline. In the following example, a ClockController is used to interactively modify the SpeedRatio of a clock. The CurrentGlobalSpeedInvalidated event and the clock's CurrentGlobalSpeed property are used to display the clock's current global speed each time its interactive SpeedRatio is changed.

  This example shows how to interactively control 
  the speed of a clock
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;
using System.Windows.Media.Animation;

namespace Microsoft.Samples.Animation.TimingBehaviors
    public class ClockControllerSpeedRatioExample : Page

        private AnimationClock myControllableClock;
        private Button speedRatioButton;
        private TextBox speedRatioSettingTextBox;
        private double doubleParseResult = 1;
        private TextBlock currentGlobalSpeedTextBlock;

        public ClockControllerSpeedRatioExample()
            StackPanel mainPanel = new StackPanel();

            // Create a rectangle to animate.
            Rectangle animatedRectangle = new Rectangle();
            animatedRectangle.Width = 100;
            animatedRectangle.Height = 100;
            animatedRectangle.Fill = Brushes.Orange;
            // Create a DoubleAnimation to
            // animate its width.
            DoubleAnimation widthAnimation = 
                new DoubleAnimation(
                    new Duration(TimeSpan.FromSeconds(5)));
            //widthAnimation.RepeatBehavior = RepeatBehavior.Forever;
            widthAnimation.AutoReverse = true;
            widthAnimation.SpeedRatio = 0.5;

            // Create a clock from the animation.
            myControllableClock = widthAnimation.CreateClock();

            // Apply the clock to the rectangle's Width property.
                Rectangle.WidthProperty, myControllableClock);    

            // Create some controls the enable the user to
            // interactively control the SpeedRatio of the clock. 
            StackPanel speedRatioDetailsPanel = new StackPanel();
            speedRatioDetailsPanel.Margin = new Thickness(0,20,0,20);
            speedRatioDetailsPanel.Orientation = Orientation.Horizontal;
            Label speedRatioLabel = new Label();
            speedRatioLabel.Content = "Speed Ratio:";

            // Create a text box so that the user can
            // specify the amount by which to seek.
            speedRatioSettingTextBox = new TextBox();
            speedRatioSettingTextBox.Text = 
            speedRatioSettingTextBox.VerticalAlignment = VerticalAlignment.Top;
            speedRatioSettingTextBox.TextChanged += 
                new TextChangedEventHandler(seekAmountTextBox_TextChanged);

            // Create a button to apply SpeedRatio changes.
            speedRatioButton = new Button();
            speedRatioButton.Content = "Apply Speed Ratio";
            speedRatioButton.Click += new RoutedEventHandler(speedRatioButton_Clicked);  


            // Display the clock's global speed information.
            Label myLabel = new Label();
            myLabel.Content = "CurrentGlobalSpeed ";
            currentGlobalSpeedTextBlock = new TextBlock();
            currentGlobalSpeedTextBlock.Text = 

            // List for speed changes.
            myControllableClock.CurrentGlobalSpeedInvalidated += 
                new EventHandler(myControllableClock_currentGlobalSpeedInvalidated);

            this.Content = mainPanel;

        // Updates the clock's SpeedRatio.
        private void speedRatioButton_Clicked(object sender, RoutedEventArgs e)

            // This statement triggers a CurrentGlobalSpeedInvalidated
            // event.
            myControllableClock.Controller.SpeedRatio = doubleParseResult; 


        // Displays the current global speed.
        private void myControllableClock_currentGlobalSpeedInvalidated(object sender, EventArgs e)

            currentGlobalSpeedTextBlock.Text = 
                + " Event triggered at: " 
                + DateTime.Now.ToString();   


        // Verifies that speedRatioSettingTextBox has valid text content.
        // If it doesn't, the speedRatioButton is disabled.
        private void seekAmountTextBox_TextChanged(object sender, TextChangedEventArgs e)

            TextBox theTextBox = (TextBox)e.Source;
            if (theTextBox.Text == null || theTextBox.Text.Length < 1
                || Double.TryParse(theTextBox.Text, 
                    null, out doubleParseResult) == false)
                speedRatioButton.IsEnabled = false;
                speedRatioButton.IsEnabled = true;



.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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