Howto dynamicly bind XML element to a TextInput using BindingUtils?

Question

The question is: Howto dynamicly bind XML element to a
TextInput component using BindingUtils?
Now I use following codes:
<!--
[Bindable] private var xml: XML =
<item><label>list1</label></item>;
// initialize code for application's initialize event
private function init(): void {
BindingUtils.bindProperty(txtDemo, "text", xml, "label");
//click event
private function test(): void {
xml.label = "something";
// txtDemo.executeBindings(); //---- no use anymore
-->
<mx:TextInput id="txtDemo"/>
<mx:Button label="Test" click="test()"/>
My really idea is when bindable xml property is changed, then
the textinput will be updated as hoped. However, no update happens
to me when I click the Test button.
But, if I make codes like that:
<mx: TextInput id="txtDemo" text="{xml.label}"/>
the text will updated when xml changs.
So, what happened, I indeed need the dynamicly bind to the
textinput compont.
Help me. thanks.

Answer 1

You could use an ObjectProxy since all subproperties will
then be bindable:
private var _xml:XML =
<item><label>list1</label></item>;
private var _opXML:ObjectProxy = new ObjectProxy(_xml);
then in your init() function you declare _opXML as the host
object with the bindable property "label"...
// initialize code for application's initialize event
public function init(): void {
BindingUtils.bindProperty(txtDemo, "text", _opXML, "label");
//click event
private function test(): void {
_opXML.label = "something";
You'll notice that if you check your original _xml.label
property with ChangeWatcher.canWatch(), it returns false. But if
you create a dedicated object with a property that can be declared
as bindable, canWatch() returns true. You'd probably be best off to
write a lightweight class that can act as your model if you want to
work with dynamic XML binding using Actionscript. This will allow
you to use a bindable getter and setter that will give you the
dynamic functionality you're looking for.
Hope that helps.