Timeline Class

Definition

Namespace:

System.Windows.Media.Animation

Assembly:

PresentationCore.dll

Defines a segment of time.

public ref class Timeline abstract : System::Windows::Media::Animation::Animatable

[System.Windows.Localizability(System.Windows.LocalizationCategory.None, Readability=System.Windows.Readability.Unreadable)]
[System.Windows.Markup.RuntimeNameProperty("Name")]
public abstract class Timeline : System.Windows.Media.Animation.Animatable

[<System.Windows.Localizability(System.Windows.LocalizationCategory.None, Readability=System.Windows.Readability.Unreadable)>]
[<System.Windows.Markup.RuntimeNameProperty("Name")>]
type Timeline = class
    inherit Animatable

Public MustInherit Class Timeline
Inherits Animatable

Inheritance

Object

DispatcherObject

DependencyObject

Freezable

Animatable

Timeline

Derived

System.Windows.Media.Animation.AnimationTimeline

System.Windows.Media.Animation.TimelineGroup

System.Windows.Media.MediaTimeline

Attributes

LocalizabilityAttribute RuntimeNamePropertyAttribute

Remarks

A timeline represents a segment of time. It provides properties that enable you to specify the length of that segment, when it should start, how many times it will repeat, how fast time progresses in that segment, and more.

Classes that inherit from the timeline class provide additional functionality, such as animation and media playback. The following are examples of some of the different types of specialized timelines available.

• Animations: An AnimationTimeline is a type of timeline that produces output values. When you associate an animation with a property, the animation updates the property's value as it plays, thereby "animating" it. For an introduction to animations, see Animation Overview. For information about the different ways to apply animations, see the Property Animation Techniques Overview.

• MediaTimelines: A MediaTimeline is a type of timeline that controls the playback of a media file.

• ParallelTimelines: A ParallelTimeline is a type of timeline that groups other timelines.

• Storyboards: A Storyboard is a special type of ParallelTimeline that provides object and property targeting information for the timelines it contains. For more information about Storyboard objects, see the Storyboards Overview.

For more information about using timelines, see the Animation Overview. For an introduction to the timing features of timelines, see the Timing Behaviors Overview.

Data Binding and Animating Timelines

Most timeline properties can be data bound or animated; however, because of the way the timing system works, data bound or animated timelines do not behave like other data bound or animated objects. To understand their behavior, it helps to understand what it means to activate a timeline.

When a timeline is applied, copies are made of the timeline and its child timelines. These copies are frozen (made read-only) and Clock objects are created from them. It's these clocks that do the actual work of animating the targeted properties. If a timeline was data bound or animated, a snapshot of its current values was made when its clock was created. Even though the original timeline might continue to change, its clock does not.

For a timeline to reflect data binding or animation changes, its clock must be regenerated. Clocks are not regenerated for you automatically. The following are several ways to apply timeline changes:

• If the timeline is or belongs to a Storyboard, you can make it reflect changes by reapplying its storyboard using a BeginStoryboard or the Begin method. This has the side effect of also restarting the animation. In code, you can use the Seek method to advance the storyboard back to its previous position.

• If you applied an animation directly to a property using the BeginAnimation method, call the BeginAnimation method again and pass it the animation that's been modified.

• If you are working directly at the clock level, create and apply a new set of clocks and use them to replace the previous set of generated clocks.

For an example of a data bound animation, see the Key Spline Animation Sample .

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.

Constructors

Timeline()	Initializes a new instance of the Timeline class.
Timeline(Nullable<TimeSpan>, Duration, RepeatBehavior)	Initializes a new instance of the Timeline class with the specified BeginTime, Duration, and RepeatBehavior.
Timeline(Nullable<TimeSpan>, Duration)	Initializes a new instance of the Timeline class with the specified BeginTime and Duration.
Timeline(Nullable<TimeSpan>)	Initializes a new instance of the Timeline class with the specified BeginTime.

Fields

AccelerationRatioProperty	Identifies the AccelerationRatio dependency property.
AutoReverseProperty	Identifies the AutoReverse dependency property.
BeginTimeProperty	Identifies the BeginTime dependency property.
DecelerationRatioProperty	Identifies for the DecelerationRatio dependency property.
DesiredFrameRateProperty	Identifies the DesiredFrameRate attached property.
DurationProperty	Identifies the Duration dependency property.
FillBehaviorProperty	Identifies the FillBehavior dependency property.
NameProperty	Identifies the Name dependency property.
RepeatBehaviorProperty	Identifies the RepeatBehavior dependency property.
SpeedRatioProperty	Identifies for the SpeedRatio dependency property.

Properties

AccelerationRatio	Gets or sets a value specifying the percentage of the timeline's Duration spent accelerating the passage of time from zero to its maximum rate.
AutoReverse	Gets or sets a value that indicates whether the timeline plays in reverse after it completes a forward iteration.
BeginTime	Gets or sets the time at which this Timeline should begin.
CanFreeze	Gets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable)
DecelerationRatio	Gets or sets a value specifying the percentage of the timeline's Duration spent decelerating the passage of time from its maximum rate to zero.
DependencyObjectType	Gets the DependencyObjectType that wraps the CLR type of this instance. (Inherited from DependencyObject)
Dispatcher	Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject)
Duration	Gets or sets the length of time for which this timeline plays, not counting repetitions.
FillBehavior	Gets or sets a value that specifies how the Timeline behaves after it reaches the end of its active period.
HasAnimatedProperties	Gets a value that indicates whether one or more AnimationClock objects is associated with any of this object's dependency properties. (Inherited from Animatable)
IsFrozen	Gets a value that indicates whether the object is currently modifiable. (Inherited from Freezable)
IsSealed	Gets a value that indicates whether this instance is currently sealed (read-only). (Inherited from DependencyObject)
Name	Gets or sets the name of this Timeline.
RepeatBehavior	Gets or sets the repeating behavior of this timeline.
SpeedRatio	Gets or sets the rate, relative to its parent, at which time progresses for this Timeline.

Attached Properties

DesiredFrameRate

Gets or sets the desired frame rate for this timeline and its child timelines.

Methods

AllocateClock()	Creates a Clock for this Timeline.
ApplyAnimationClock(DependencyProperty, AnimationClock, HandoffBehavior)	Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable)
ApplyAnimationClock(DependencyProperty, AnimationClock)	Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable)
BeginAnimation(DependencyProperty, AnimationTimeline, HandoffBehavior)	Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable)
BeginAnimation(DependencyProperty, AnimationTimeline)	Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable)
CheckAccess()	Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject)
ClearValue(DependencyProperty)	Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier. (Inherited from DependencyObject)
ClearValue(DependencyPropertyKey)	Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey. (Inherited from DependencyObject)
Clone()	Creates a modifiable clone of this Timeline, making deep copies of this object's values.
CloneCore(Freezable)	Makes the instance a clone (deep copy) of the specified Freezable using base (non-animated) property values. (Inherited from Freezable)
CloneCurrentValue()	Creates a modifiable clone of this Timeline object, making deep copies of this object's current values.
CloneCurrentValueCore(Freezable)	Makes the instance a modifiable clone (deep copy) of the specified Freezable using current property values. (Inherited from Freezable)
CoerceValue(DependencyProperty)	Coerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject. (Inherited from DependencyObject)
CreateClock()	Creates a new, controllable Clock from this Timeline. If this Timeline has children, a tree of clocks is created with this Timeline as the root.
CreateClock(Boolean)	Creates a new Clock from this Timeline and specifies whether the new Clock is controllable. If this Timeline has children, a tree of clocks is created with this Timeline as the root.
CreateInstance()	Initializes a new instance of the Freezable class. (Inherited from Freezable)
CreateInstanceCore()	When implemented in a derived class, creates a new instance of the Freezable derived class. (Inherited from Freezable)
Equals(Object)	Determines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject)
Freeze()	Makes the current object unmodifiable and sets its IsFrozen property to true. (Inherited from Freezable)
FreezeCore(Boolean)	Makes this Timeline unmodifiable or determines whether it can be made unmodifiable.
GetAnimationBaseValue(DependencyProperty)	Returns the non-animated value of the specified DependencyProperty. (Inherited from Animatable)
GetAsFrozen()	Creates a frozen copy of the Freezable, using base (non-animated) property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetAsFrozenCore(Freezable)	Makes this instance a clone of the specified Timeline object.
GetCurrentValueAsFrozen()	Creates a frozen copy of the Freezable using current property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetCurrentValueAsFrozenCore(Freezable)	Makes this instance a frozen clone of the specified Timeline. Resource references, data bindings, and animations are not copied, but their current values are.
GetDesiredFrameRate(Timeline)	Gets the desired frame rate of the specified Timeline.
GetHashCode()	Gets a hash code for this DependencyObject. (Inherited from DependencyObject)
GetLocalValueEnumerator()	Creates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject. (Inherited from DependencyObject)
GetNaturalDuration(Clock)	Returns the length of a single iteration of this Timeline.
GetNaturalDurationCore(Clock)	Returns the length of a single iteration of this Timeline. This method provides the implementation for GetNaturalDuration(Clock).
GetType()	Gets the Type of the current instance. (Inherited from Object)
GetValue(DependencyProperty)	Returns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject)
InvalidateProperty(DependencyProperty)	Re-evaluates the effective value for the specified dependency property. (Inherited from DependencyObject)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnChanged()	Called when the current Freezable object is modified. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject, DependencyProperty)	This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject)	Ensures that appropriate context pointers are established for a DependencyObjectType data member that has just been set. (Inherited from Freezable)
OnPropertyChanged(DependencyPropertyChangedEventArgs)	Overrides the DependencyObject implementation of OnPropertyChanged(DependencyPropertyChangedEventArgs) to also invoke any Changed handlers in response to a changing dependency property of type Freezable. (Inherited from Freezable)
ReadLocalValue(DependencyProperty)	Returns the local value of a dependency property, if it exists. (Inherited from DependencyObject)
ReadPreamble()	Ensures that the Freezable is being accessed from a valid thread. Inheritors of Freezable must call this method at the beginning of any API that reads data members that are not dependency properties. (Inherited from Freezable)
SetCurrentValue(DependencyProperty, Object)	Sets the value of a dependency property without changing its value source. (Inherited from DependencyObject)
SetDesiredFrameRate(Timeline, Nullable<Int32>)	Sets the desired frame rate of the specified Timeline.
SetValue(DependencyProperty, Object)	Sets the local value of a dependency property, specified by its dependency property identifier. (Inherited from DependencyObject)
SetValue(DependencyPropertyKey, Object)	Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property. (Inherited from DependencyObject)
ShouldSerializeProperty(DependencyProperty)	Returns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject)
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)
WritePostscript()	Raises the Changed event for the Freezable and invokes its OnChanged() method. Classes that derive from Freezable should call this method at the end of any API that modifies class members that are not stored as dependency properties. (Inherited from Freezable)
WritePreamble()	Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the beginning of any API that writes to data members that are not dependency properties. (Inherited from Freezable)

Events

Changed	Occurs when the Freezable or an object it contains is modified. (Inherited from Freezable)
Completed	Occurs when this timeline has completely finished playing: it will no longer enter its active period.
CurrentGlobalSpeedInvalidated	Occurs when the rate at which time progresses for the timeline's clock changes.
CurrentStateInvalidated	Occurs when the CurrentState property of the timeline's Clock is updated.
CurrentTimeInvalidated	Occurs when the CurrentTime property of the timeline's Clock is updated.
RemoveRequested	Occurs when the clock created for this timeline or one of its parent timelines is removed.

See also

• Animation Timing Behavior Sample