title: Get selectedIndex in Datagrid from itemRenderer
body: <p>I have a DataGrid and the first column cells have an itemRenderer with an embebed image and doubleClick event linked.</p>
  
  <p>So, when o double click event occur, this renderer catch the event and the handler. The question is that I would like to dispatch an Event with the index of the selected item in the Datagrid and I do not find out how to ge it.</p>
  
  <pre><code>s:GridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" 
                  xmlns:s="library://ns.adobe.com/flex/spark" 
                  xmlns:mx="library://ns.adobe.com/flex/mx" clipAndEnableScrolling="true"
                  width="50" height="30"&gt;
  
  &lt;fx:Script&gt;
      &lt;![CDATA[
          import events.EditItemEvent;
  
          import mx.controls.Alert;
          override public function prepare(hasBeenRecycled:Boolean):void {}
  
          protected function btn_edit_doubleClickHandler(event:MouseEvent):void {
              /* here I dispatchEvent with the 'index' of the selectedItem of the datagrid */
          }
  
      ]]&gt;
  &lt;/fx:Script&gt;
  &lt;s:Image id="btn_edit" horizontalCenter="0" source="@Embed('assets/images/edit_icon.png')"
           verticalCenter="0"
           doubleClickEnabled="true"
           doubleClick="btn_edit_doubleClickHandler(event)"/&gt;
  </code></pre>
  
  <p></p>
  
  <p>Any idea?</p>