Maintains run-time timing state for a Timeline.
Assembly: PresentationCore (in PresentationCore.dll)
Thetype exposes the following members.
|Controller||Gets a ClockController that can be used to start, pause, resume, seek, skip, stop, or remove this .|
|CurrentGlobalSpeed||Gets the rate at which the clock's time is currently progressing, compared to real-world time.|
|CurrentGlobalTime||Gets the current global time, as established by the WPF timing system.|
|CurrentIteration||Get the current iteration of this clock.|
|CurrentProgress||Gets the current progress of this within its current iteration.|
|CurrentState||Gets a value indicating whether the clock is currently Active, Filling, or Stopped.|
|CurrentTime||Gets this clock's current time within its current iteration.|
|Dispatcher||Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject.)|
|HasControllableRoot||Gets a value that indicates whether this is part of a controllable clock tree.|
|IsPaused||Gets a value that indicates whether this , or any of its parents, is paused.|
|NaturalDuration||Gets the natural duration of this clock's Timeline.|
|Parent||Gets the clock that is the parent of this clock.|
|Timeline||Gets the Timeline from which this was created.|
|CheckAccess||Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)|
|DiscontinuousTimeMovement||When implemented in a derived class, will be invoked whenever a clock repeats, skips, or seeks.|
|Equals(Object)||Determines whether the specified object is equal to the current object. (Inherited from Object.)|
|Finalize||Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)|
|GetCanSlip||Returns whether the has its own external time source, which may require synchronization with the timing system.|
|GetCurrentTimeCore||Gets this clock's current time within its current iteration.|
|GetHashCode||Serves as the default hash function. (Inherited from Object.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|SpeedChanged||When implemented in a derived class, will be invoked whenever a clock begins, skips, pauses, resumes, or when the clock's SpeedRatio is modified.|
|Stopped||When implemented in a derived class, will be invoked whenever a clock is stopped using the Stop method.|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
|VerifyAccess||Enforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)|
|Completed||Occurs when this clock has completely finished playing.|
|CurrentGlobalSpeedInvalidated||Occurs when the clock's speed is updated.|
|CurrentStateInvalidated||Occurs when the clock's CurrentState property is updated.|
|CurrentTimeInvalidated||Occurs when this clock's CurrentTime becomes invalid.|
|RemoveRequested||Occurs when the Remove method is called on this or one of its parent clocks.|
A Timeline, by itself, doesn't actually do anything other than describe a segment of time. It's the timeline's object that does the real work: it maintains timing-related run-time state for the timeline.
In most cases, a clock is created automatically for your timeline. When you animate by using a Storyboard or the BeginAnimation method, clocks are automatically created for your timelines and animations and applied to their targeted properties. For examples, see How to: Animate a Property by Using a Storyboard and How to: Animate a Property Without Using a Storyboard.
You can also create a explicitly by using the CreateClock method. In performance-intensive scenarios, such as animating large numbers of similar objects, managing your own use can provide performance benefits.
Clocks are arranged in trees that match the structure of the Timeline objects tree from which they are created. The root clock of such a timing tree can be interactively manipulated (paused, resumed, stopped, and so on) by retrieving its Controller. Non-root clocks cannot be directly controlled.
Once created, a clock cannot be modified (but it can be manipulated).
Using a Timeline as a Timer
A timeline's clock will only progress when there's an event handler associated with it or (in the case of an AnimationClock object) it is associated with a property. For this reason (and others), it's not recommended that you use a Timeline as a timer.
Derived classes should implement GetCurrentTimeCore if they want to modify how time flows for this clock. Derived classes can be made to do additional work when the clock repeats, skips, seeks, begins, pauses, resumes, or stops by overriding the DiscontinuousTimeMovement, SpeedChanged, and Stopped methods.
This example shows how to use objects to animate a property.
There are three ways to animate a dependency property:
Storyboard objects and the BeginAnimation method enable you to animate properties without directly creating and distributing clocks (for examples, see How to: Animate a Property by Using a Storyboard and How to: Animate a Property Without Using a Storyboard); clocks are created and distributed for you automatically.
The following example shows how to create an AnimationClock and apply it to two similar properties.
' ' This example shows how to create and apply ' an AnimationClock. ' Imports System Imports System.Windows Imports System.Windows.Controls Imports System.Windows.Media Imports System.Windows.Shapes Imports System.Windows.Media.Animation Namespace Microsoft.Samples.Animation.TimingBehaviors Public Class AnimationClockExample Inherits Page Private myScaleTransform As ScaleTransform Public Sub New() Me.WindowTitle = "Opacity Animation Example" Me.Background = Brushes.White Dim myStackPanel As New StackPanel() myStackPanel.Margin = New Thickness(20) ' Create a button that with a ScaleTransform. ' The ScaleTransform will animate when the ' button is clicked. Dim myButton As New Button() myButton.Margin = New Thickness(50) myButton.HorizontalAlignment = HorizontalAlignment.Left myButton.Content = "Click Me" myScaleTransform = New ScaleTransform(1,1) myButton.RenderTransform = myScaleTransform ' Associate an event handler with the ' button's Click event. AddHandler myButton.Click, AddressOf myButton_Clicked myStackPanel.Children.Add(myButton) Me.Content = myStackPanel End Sub ' Create and apply and animation when the button is clicked. Private Sub myButton_Clicked(ByVal sender As Object, ByVal e As RoutedEventArgs) ' Create a DoubleAnimation to animate the ' ScaleTransform. Dim myAnimation As New DoubleAnimation(1, 5, New Duration(TimeSpan.FromSeconds(5))) ' "To" value - "From" value myAnimation.AutoReverse = True ' Create a clock the for the animation. Dim myClock As AnimationClock = myAnimation.CreateClock() ' Associate the clock the ScaleX and ' ScaleY properties of the button's ' ScaleTransform. myScaleTransform.ApplyAnimationClock(ScaleTransform.ScaleXProperty, myClock) myScaleTransform.ApplyAnimationClock(ScaleTransform.ScaleYProperty, myClock) End Sub End Class End Namespace
For an example showing how to interactively control a after it starts, see How to: Interactively Control a Clock.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)