"Canceling" an event -- calling event.preventDefault() -- doesn't stop it from bubbling. This is what event.stopPropogation() and event.stopImmediatePropogation() do.
Calling event.preventDefault() simply sets a flag in the event object which can later be queried by calling event.isDefaultPrevented(). This flag doesn't affect event propogation. It's up to the class that dispatched the event -- or subsequent listeners -- to decide what to do if this flag gets set, indicating a request for event cancellation. For example, if you cancel a 'textInput" event dispatched by a TextField, then TextField won't insert the characters. The typical pattern in a dispatcher in this case is var event:Event = new SomeEvent("aboutToDoSomething"); dispatchEvent(event); if (!event.isDefaultPrevented()) doSomething(); Gordon Smith Adobe Flex SDK Team From: flexcoders@yahoogroups.com [mailto:flexcod...@yahoogroups.com] On Behalf Of Julien Nicoulaud Sent: Wednesday, July 22, 2009 11:20 AM To: flexcoders@yahoogroups.com Subject: Re: [flexcoders] Re: Event's cancelable You can cancel an event with myEvent.preventDefault(). This is often useful. For example, KeyboardEvents are not cancelable, this is an important thing to know when you override text inputs default behaviour. Julien Nicoulaud http://flex.aixo.fr 2009/7/22 postwick <p...@ubeek.com<mailto:p...@ubeek.com>> Events propagate through the hierarchy of objects. If necessary, you can stop them (cancel them) once they get to a certain point in the propagation. http://livedocs.adobe.com/flex/3/html/help.html?content=events_08.html Specifically, the section on Bubbling answers your question. --- In flexcoders@yahoogroups.com<mailto:flexcoders%40yahoogroups.com>, "markflex2007" <markflex2...@...> wrote: > > The format for Event constructor like this > Event(event_type:String, bubbles:Boolean, cancelable:Boolean) > > I do not understand what the "cancelable" used for and how to use it. > > Please give me a idea. > > Thanks > > > Mark >