Interface for class capable of handling events.
| Method | Description | 
|---|---|
| HandleEvent | Handle an event. | 
| HasBubbleUpHandlers | Returns true if event handlers for the event propagation BubbleUp phase, have been attached on this object. | 
| HasTrickleDownHandlers | Returns true if event handlers, for the event propagation TrickleDown phase, are attached to this object. | 
| SendEvent | Sends an event to the event handler. |