Question

I’m trying to implement a binding between some custom-built models and just beginning to dabble with the whole mx.binding.* collection. I tried this simple, stripped down example, but can’t get the binding working correctly. Can somebody tell me where I’m going wrong?

// Model
package  
{
 import flash.events.EventDispatcher;

 public class Model extends EventDispatcher
 {
  private var m_count:uint = 0;

  [Bindable]
  public function get Count():uint
  {
   return this.m_count;
  }

  public function set Count(c:uint):void
  {
   this.m_count = c;
  }
 }
}

And this is what the application MXML looks like

// MXML
<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:core="*" creationComplete="this.init();">
 <mx:Script>
  <![CDATA[
  import flash.events.Event;
  import flash.utils.describeType;
  import mx.binding.utils.ChangeWatcher;

  [Bindable]
  public var model:Model;

  public function init():void
  {
   var _this:Object = this;

   this.addEventListener(Event.ENTER_FRAME, function(e:Event):void {
    _this.model.Count++;
   });


   this.model = new Model();

   trace(ChangeWatcher.canWatch(this.model, "Count")); // This always returns false for some reason
   trace(describeType(this.model));
  }

  public function UpdateText(s:String):void
  {
   trace(s);
  }
  ]]>
 </mx:Script>
 <mx:Text text="{this.model.Count}" creationComplete="trace(this);" />
</mx:WindowedApplication>

Update: I tried an even more bare-bones version as shown below.

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="this.m_init();">
    <mx:Script>
        <![CDATA[
        import mx.binding.utils.ChangeWatcher;

        [Bindable] public var m:Object = new Object();

        public function m_init():void
        {
            trace(ChangeWatcher.canWatch(this, "m"));
        }
        ]]>
    </mx:Script>
    <mx:Text text="{this.m}" />
</mx:Application>

Still. Doesn’t. Work. ChangeWatcher.canWatch still returns false, although the textfield does display [object Object].

Answer 1

I removed all files inside the obj folder under the project and the problem seems to have gone away. It might have been that FlashDevelop was using older compiled binaries out of this folder, which made the output go out of sync with the source code.

Evidence to support this lies in two things. Changing the SDK did not affect the output on my own computer, which ruled out any SDK-specific issues. So I created a new project in another IDE on the same computer and copy-pasted the code into that one. This time it worked. That’s when I thought it might be the cache and went in and deleted it.

In hindsight, I should have renamed it, and later tried to compile with the old cache in place again. That would have been conclusive.