EventTrigger Class

Definition

Namespace:

Windows.UI.Xaml

Represents a trigger that applies a set of actions (animation storyboards) in response to an event. Not commonly used. See Remarks.

public ref class EventTrigger sealed : TriggerBase

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
/// [Windows.UI.Xaml.Markup.ContentProperty(Name="Actions")]
/// [Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
class EventTrigger final : TriggerBase

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
[Windows.UI.Xaml.Markup.ContentProperty(Name="Actions")]
[Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
public sealed class EventTrigger : TriggerBase

Public NotInheritable Class EventTrigger
Inherits TriggerBase

<EventTrigger>
  oneOrMoreBeginStoryboards
</EventTrigger>
 

Inheritance

Object Platform::Object IInspectable DependencyObject TriggerBase EventTrigger

Attributes

ActivatableAttribute ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute ContentPropertyAttribute

Windows requirements

Device family	Windows 10 (introduced in 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v1.0)

Examples

This XAML example shows the basic structure for using FrameworkElement.Triggers with its default FrameworkElement.Loaded trigger behavior to run a storyboarded animation. This XAML shows the EventTrigger and BeginStoryboard container elements in proper relationship with each using their XAML content property syntax and unnecessary property element tags omitted.

<Canvas Width="200" Height="200" x:Name="animatedcanvas" Background="Red">
    <Canvas.Triggers>
        <EventTrigger>
            <BeginStoryboard>
                <Storyboard x:Name="ColorStoryboard">
                   <!-- Animate the background of the canvas to green over 4 seconds. -->
                    <ColorAnimation Storyboard.TargetName="animatedcanvas"
                      Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)"
                      To="Green" Duration="0:0:4"/>
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Canvas.Triggers>
</Canvas>

Remarks

Triggers, EventTrigger, Actions and BeginStoryboard are not commonly used. These API mainly exist for compatibility in XAML originally used for Microsoft Silverlight. For most scenarios where event triggers were used previously, do one of these:

• Use built-in animations from the animation library. See Quickstart: Animating your UI using the animation library.
• For events in control templates, use visual states and VisualStateManager. See Storyboarded animations for visual states or Quickstart: Control templates.
• For app-specific UI animations, define a Loaded handler on the page. This handler can reference a Storyboard that's defined in page-level resources, and call the Begin method on that Storyboard. See Storyboarded animations.

If you do choose to use Triggers, in Windows Runtime XAML, the default behavior for event triggers and the only event that can be used to invoke an EventTrigger is FrameworkElement.Loaded. Because that's both the default and the only enabled behavior, don't set the RoutedEvent attribute. Just use the XAML <EventTrigger>. If you set RoutedEvent explicitly (not recommended), the only XAML that works is <EventTrigger RoutedEvent="FrameworkElement.Loaded">. Unqualified "Loaded", or any other value, throws a parse exception. For more info, see Triggers.

Constructors

EventTrigger()

Initializes a new instance of the EventTrigger class.

Properties

Actions	Gets the collection of BeginStoryboard objects that this EventTrigger maintains.
Dispatcher	Gets the CoreDispatcher that this object is associated with. The CoreDispatcher represents a facility that can access the DependencyObject on the UI thread even if the code is initiated by a non-UI thread. (Inherited from DependencyObject)
RoutedEvent	Gets or sets the name of the event that initiates the trigger. Not commonly set, see Remarks.

Methods

ClearValue(DependencyProperty)	Clears the local value of a dependency property. (Inherited from DependencyObject)
GetAnimationBaseValue(DependencyProperty)	Returns any base value established for a dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject)
GetValue(DependencyProperty)	Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject)
ReadLocalValue(DependencyProperty)	Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject)
RegisterPropertyChangedCallback(DependencyProperty, DependencyPropertyChangedCallback)	Registers a notification function for listening to changes to a specific DependencyProperty on this DependencyObject instance. (Inherited from DependencyObject)
SetValue(DependencyProperty, Object)	Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject)
UnregisterPropertyChangedCallback(DependencyProperty, Int64)	Cancels a change notification that was previously registered by calling RegisterPropertyChangedCallback. (Inherited from DependencyObject)

See also

• TriggerBase
• Triggers
• Storyboarded animations for visual states
• Quickstart: Control templates