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Flash Player 6.0.79.
Flash MX 2004.
Usage 1:
on(scroll){
// your code here
}
Usage 2:
listenerObject= new Object();listenerObject.scroll = function(eventObject){// your code here }comboBoxInstance.addEventListener("scroll",listenerObject)
Along with the standard event object properties, the scroll event has one additional property, direction. It is a string with two possible values "horizontal" or "vertical". For a ComboBox scroll event, the value is always "vertical".
Event; broadcast to all registered listeners when the drop-down list is scrolled. This is a List component event that is available to the ComboBox.
The first usage example uses an on() handler and must be attached directly to a ComboBox component instance. The keyword this, used inside an on() handler attached to a component, refers to the component instance. For example, the following code, attached to the ComboBox component instance myBox, sends "_level0.myBox" to the Output panel:
on(scroll){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance (comboBoxInstance) dispatches an event (in this case, scroll) and the event is handled by a function attached to 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 a set of properties that contains information about the event. You can use these properties to write code that handles the event. For more information about event objects, see Event Objects.
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.
The following example sends a message to the Output panel that indicates which item index number has been scrolled to:
form.scroll = function (eventObj) {
trace("The list had been scrolled to item # " + eventObj.target.vPosition);
}
myCombo.addEventListener("scroll", form);
UIEventDispatcher.addEventListener()
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