[flexcoders] Closures in ActionScript 3?

[Keith Hughitt]

Could someone please explain to me how closures work in ActionScript? I
am attempting to create a set of Flex Form fields, and assign an
event-handler to each of them, however, it seems that after creation,
all of the fields have the same event handler.

For example:

var i:int = 0;
           for each (var item:Object in this._myItems) {
                 var f:FormItem = new FormItem();
                 f.label = item.header;

                 var input:TextInput = new TextInput();

                 // Setup event-handler
                 var self:MyClass = this;

                 input.addEventListener("change", function (e:Event):void
{
                     Alert.show("Event-hanlder #: " + String(i));
                  });

                 i++;

                 // Add text input to FormItem
                 f.addChild(input);

                 // Save a reference to the form control
                 item.ui = f;
                 addChild(f);
             }

So I would expect that the number displayed when I change any given
field matched the order of the field on the screen. When I run the code,
however, no matter which field I adjust, the number is always the same
(it is the number of the last form item to be added).

It appears that what is happening is that a single function is being
created, and each input field has a reference to that same function.

Any suggestions? Any help would be greatly appreciated.

Thanks!
Keith