Articolo
11/18/2011

EventTrigger Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Represents a trigger that applies a set of actions (animation storyboards) in response to an event.

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.TriggerBase
      System.Windows.EventTrigger

Namespace: System.Windows
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
<ContentPropertyAttribute("Actions", True)> _
Public NotInheritable Class EventTrigger _
    Inherits TriggerBase

[ContentPropertyAttribute("Actions", true)]
public sealed class EventTrigger : TriggerBase

<EventTrigger>
  oneOrMoreBeginStoryboards
</EventTrigger>

XAML Values

oneOrMoreBeginStoryboards
One or more BeginStoryboard object elements. Object elements defined here become members of the TriggerActionCollection that is the value of the Actions property, if you use code to examine that collection at run time.

The EventTrigger type exposes the following members.

Constructors

	Name	Description
	EventTrigger	Initializes a new instance of the EventTrigger class.

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Properties

	Name	Description
	Actions	Gets the collection of BeginStoryboard objects that this EventTrigger maintains.
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	RoutedEvent	Gets or sets the name of the event that initiates the trigger.

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Methods

	Name	Description
	CheckAccess	Determines whether the calling thread has access to this object. (Inherited from DependencyObject.)
	ClearValue	Clears the local value of a dependency property. (Inherited from DependencyObject.)
	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 the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetAnimationBaseValue	Returns any base value established for a Silverlight dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetValue	Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ReadLocalValue	Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)
	SetValue	Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

EventTrigger and the object.Triggers property element usage on elements are supported by Silverlight, but using this technique is discouraged for current applications. EventTrigger can only support a triggering action for the Loaded event (you name the event in the EventTrigger.RoutedEvent property.) This makes an EventTrigger unsuitable for most run-time interactions. Instead of using EventTrigger and the Triggers property, consider one of the following two alternatives:

For animating properties on objects that are not controls, place the storyboard in the general Resources for a page or application. Then assign an event handler on the element where you would have placed "Triggers". The event handler, when responding to the relevant event, should retrieve the storyboard from the resource dictionary. You then call Begin on the retrieved Storyboard.
For animating properties on objects that are controls (derive from Control), use the VisualStateManager technique, and run the appropriate animations based on state of or inputs to the control by calling GoToState.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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