Interface for classes capable of having callbacks to handle events.
|HandleEvent||Handle an event, most often by executing the callbacks associated with the event.|
|HasBubbleUpHandlers||Return 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.|
|RegisterCallback||Adds an event handler to the instance. If the event handler has already been registered for the same phase (either TrickleDown or BubbleUp) then this method has no effect.|
|SendEvent||Sends an event to the event handler.|
|UnregisterCallback||Remove callback from the instance.|