How do I dynamically populate the options in a combobox inside of a grid based on another row in Flex?

Question

I'm trying to setup a DataGrid that contains a column of combo boxes. The values of the combo boxes are defined by data specific to that row. I cannot get this to work though, I'm asking for a solution to this, either fixing what I have below or a recommendation on a different way.

One of the columns of my DataGrid has an object derived from a ComboBox for an ItemEditor. The itemEditor is set like this:

 <mx:DataGridColumn editorDataField="selectedItem" dataField="type" editable="true" >
  <mx:itemEditor>
   <mx:Component>
   <FilterCell:SelectCellBase initialize="set_combo()" grid="{this}"/>
   </mx:Component>
  </mx:itemEditor>
 </mx:DataGridColumn>

So that when the itemEditor is generated (when the user double clicks on the cell) the data is populated.

Then, the SelectCellBase set_combo() function is defined as such:

      public function set_combo( ) : void 
      {
       var type : String = grid.dataProvider[grid.selectedIndex]['type'];

       if( 'text' == type )
       {
        this.dataProvider = text;
       }
       else
       {
        this.dataProvider = number;
       }
      }

This implementation isn't working though because when I try to call grid.selectedIndex this always seems to return -1.

What am I doing wrong, or what better way is there to do this?

Answer 1

Your problem is that when you're inside of an <mx:Component> the scope is local, and no longer set to the outside MXML file. So when you have:

<mx:Component>
<FilterCell:SelectCellBase initialize="set_combo()" grid="{this}"/>
</mx:Component>

the "this" you're referring to is the inline component you've defined, not the base MXML component you're working on. The easy fix is to change it to

<mx:Component>
<FilterCell:SelectCellBase initialize="set_combo()" grid="{outerDocument}"/>
</mx:Component>

the outerDocument variable is automatically set when you're inside of an <mx:Component> tag, and can be used to access anything needed from the parent scope.