Absolute / Relative Flex Datagrid Component RowIndex

For performance reasons, Flex Datagrid component swap elements into rows while scolling. Flex don’t create as many rows as entries in the dataprovider. So to get the actual dataprovider related index, when using for example a listener to a mouse event on the datagrid component :

private function onItemRollOver(event:ListEvent):void
{
    var rowIndex:int = event.rowIndex;  // or myDG.listData.rowIndex
}

the rowIndex here is relative to visible rows in the datagrid. One way to get the  right one “related to dataprovider”  is to add the datagrid vertical scroll position

var rowIndex:int = myDG.listData.rowIndex + myDG.verticalScrollPosition;

If you have  a better way to do it, please leave a comment …