There’s other (possibly more elegant) solutions out there on the web, but I came up with this today when faced with trying to set the initial “selectedIndex” of a ComboBox whose contents are populated dynamically.  Unlike HTML, it’s not as simple as just marking one of the “options” as selected, but fortunately, it’s not a lot harder.

1
2
3
4
5
6
7
8
9
10
11
12
13
14

<mx:Script>
  <![CDATA[
    private function locateLabel( source : ArrayCollection, label : String )
    {
        for( var i=0; i<source.length; i++ )
        {
          if(source[i].label == label ) return i;
        }
        return 0;
    }
  ]]>
</mx:Script>
 
<mx:ComboBox dataProvider="{model.stateList}" selectedIndex="{locateLabel(model.stateList,model.address.state)}" />

This method triggers binding whenever model.stateList or model.address.state changes, and updates the combo-box position accordingly. To me this is a bit cleaner than sub-classing the ComboBox, which was the primary other method that I saw recommended, but I welcome other suggestions, if there’s an even easier method I’ve missed.