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Clock.CurrentGlobalSpeed Property

Gets the rate at which the clock's time is currently progressing, compared to real-world time.

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

public Nullable<double> CurrentGlobalSpeed { get; }
/** @property */
public Nullable<double> get_CurrentGlobalSpeed ()

public function get CurrentGlobalSpeed () : Nullable<double>

You cannot use this property in XAML.

Property Value

The rate at which this clock's time is current progressing, compared to real-world time. If the clock is stopped, this property returns a null reference (Nothing in Visual Basic).

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;

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0