User Guide

200 Chapter 6: Components Dictionary
See also
ComboBox.close()
ComboBox.open
Availability
Flash Player 6 (6.0 79.0).
Edition
Flash MX 2004.
Usage
Usage 1:
on(open){
// your code here
}
Usage 2:
listenerObject = new Object();
listenerObject.open = function(eventObject){
// your code here
}
comboBoxInstance.addEventListener("open", listenerObject)
Description
Event; broadcast to all registered listeners when the drop-down list is completely open.
The first usage example uses an
on() handler and must be attached directly to a ComboBox
instance. The keyword
this, used in an on() handler attached to a component, refers to the
component instance. For example, the following code, attached to the ComboBox instance
myBox, sends “_level0.myBox” to the Output panel:
on(open){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance
(
comboBoxInstance) dispatches an event (in this case, open) and the event is handled by a
function, also called a handler, on a listener object (
listenerObject) that you create. You define
a method with the same name as the event on the listener object; the method is called when the
event is triggered. When the event is triggered, it automatically passes an event object
(
eventObject) to the listener object method. Each event object has properties that contain
information about the event. You can use these properties to write code that handles the event.
For more information, see “EventDispatcher class” on page 415.
Finally, you call the
addEventListener() method on the component instance that broadcasts
the event to register the listener with the instance. When the instance dispatches the event, the
listener is called.