Question

The following displays a ComboBox with the text ‘Select One’:

**This is pseudo code*

<?xml version='1.0' encoding='utf-8'?> <mx:Application xmlns:mx='http://www.adobe.com/2006/mxml' layout='absolute'>     <mx:ComboBox prompt='Select One'>         <mx:dataProvider>             <mx:Array>                 <mx:Object label='Obj 1' />                 <mx:Object label='Obj 2' />                 <mx:Object label='Obj 3' />             </mx:Array>         </mx:dataProvider>     </mx:ComboBox> </mx:Application> 

However, the following displays a ComboBox with the text ‘Obj 1’ (the label of the first item):

<?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 promptText:String = 'Select One';         ]]>     </mx:Script>      <mx:ComboBox prompt='{promptText}'>         <mx:dataProvider>             <mx:Array>                 <mx:Object label='Obj 1' />                 <mx:Object label='Obj 2' />                 <mx:Object label='Obj 3' />             </mx:Array>         </mx:dataProvider>     </mx:ComboBox> </mx:Application> 

Why can’t I use a Bindable String for the prompt???

Answer 1

This worked:

<?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 promptText:String = 'Select One';         ]]>     </mx:Script>      <mx:ComboBox selectedIndex='-1' prompt='{promptText}'>         <mx:dataProvider>             <mx:Array>                 <mx:Object label='Obj 1' />                 <mx:Object label='Obj 2' />                 <mx:Object label='Obj 3' />             </mx:Array>         </mx:dataProvider>     </mx:ComboBox> </mx:Application> 

I can’t figure out why I have to explicitly set selectedIndex to -1, but, it works!