A problem with binding a visual control to a class property defined with a getter&setter pair

Question

hi,
I am having the following problem (simplified here for
clarity):
I am using a class for data model with a property named
x (using a getter & setter) as follows:
quote:
[Bindable]
public class MyData
private var _x :String;
public function MyData()
_x = "default value";
public function set x(value:String):void {
trace("setting x with: '" + value + "'");
_x = String(value);
public function get x():String {
trace("getting x: '"+_x+"'");
return _x;
I then linked (binded) the
x property to a TextInput, as follows:
quote:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
layout="absolute">
<mx:Script>
<![CDATA[
[Bindable]
private var _data:MyData = new MyData();
]]>
</mx:Script>
<mx:TextInput id="inputX"
text="{_data.x}" />
</mx:Application>
When loaded,
inputX is set with the "default value". However, when
changing the value of
inputX the value of
_data.x remains unchanged (in this sample - there are no
trace messages from the setter).
I have tried numerous variations using <mx:Bindind
...>, mx.bindinding.utils.BindingUtils, changing order of setter
and getter, and more.
The only solution i could find for now is to add a change
event handler to the
inputX control as follows:
quote:
<mx:TextInput id="inputX" text="{_data.x}"
change="_data.x=inputX.text"/>
Is there something i did wrong? or is it ... simply ... a bug
thanx,

Answer 1

hi,
thanx for your quick reply.
The actual problem was the that _data.x initialization should
not be done in the MyData constructor, but after the object is
fully created, as follows:
[Bindable]
private var _data:MyData = new MyData();
// called in the application's initialize event
public function init():void {
_data.x = "default value";
After this, adding the <mx:Binding> does the trick for
the inputX.text --> _data.x binding, and there's no need to add
"this". I simply have assumed (being a novice flex developer) that
using <mx:TextInput id="inputX" text="{_data.x}" /> binds for
both directions inputX.text <--> _data.x.
thanx again,
yaron