Clock Class

Definition

Namespace:

System.Windows.Media.Animation

Assembly:

PresentationCore.dll

Maintains run-time timing state for a Timeline.

public ref class Clock : System::Windows::Threading::DispatcherObject

public class Clock : System.Windows.Threading.DispatcherObject

type Clock = class
    inherit DispatcherObject

Public Class Clock
Inherits DispatcherObject

Inheritance

Object

DispatcherObject

Clock

Derived

System.Windows.Media.Animation.AnimationClock

System.Windows.Media.Animation.ClockGroup

System.Windows.Media.MediaClock

Remarks

A Timeline, by itself, doesn't actually do anything other than describe a segment of time. It's the timeline's Clock 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 Clock explicitly by using the CreateClock method. In performance-intensive scenarios, such as animating large numbers of similar objects, managing your own Clock 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.

Notes to Inheritors

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.

Constructors

Clock(Timeline)

Initializes a new instance of the Clock class, using the specified Timeline as a template. The new Clock object has no children.

Properties

Controller	Gets a ClockController that can be used to start, pause, resume, seek, skip, stop, or remove this Clock.
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 Clock 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 Clock is part of a controllable clock tree.
IsPaused	Gets a value that indicates whether this Clock, 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 Clock was created.

Methods

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)
GetCanSlip()	Returns whether the Clock 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)

Events

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 Clock or one of its parent clocks.