When user selects multiple rows then how to set background color of selected rows based on the value of one of the column?

The main crux is the item renderer to be used by the datagrid. We can then set color of one of the column or al the columns of the selected row of datagrid.
 

package
{
    import flash.display.Graphics;
    import flash.events.Event;
    
    import mx.controls.AdvancedDataGrid;
    import mx.controls.Label;
    import
mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
    import mx.events.ListEvent;

    public class ADGItemrenderer extends Label
    {
        public function ADGItemrenderer()
        {
            addEventListener(ListEvent.ITEM_CLICK,callInvalidate);
        }
       
        public function callInvalidate(event:Event):void{
            invalidateDisplayList();
        }
        override protected function
updateDisplayList(unscaledWidth:Number,
unscaledHeight:Number):void{
            var g:Graphics = graphics;
           
            super.updateDisplayList(unscaledWidth, unscaledHeight);
            g.clear();
           
            if(super.data){
                    var advancedDataGrid:AdvancedDataGrid =
(listData)?AdvancedDataGrid((listData).owner):null;
                    var column:AdvancedDataGridColumn =
(advancedDataGrid)?advancedDataGrid.columns[listData.columnIndex]
as AdvancedDataGridColumn:null;
                    if(advancedDataGrid.isItemSelected(data)){
                            if(data.severity <300){
                                /*change color accordingly*/
                                g.beginFill(0xCC0033);
                                g.drawRect(0, 0, unscaledWidth,
unscaledHeight);
                                g.endFill();
                            }else if(data.severity <400){
                                /*make it some other color*/
                                g.beginFill(0x00FF00);
                                g.drawRect(0, 0, unscaledWidth,
unscaledHeight);
                                g.endFill();
                            }else{
                                g.beginFill(0x0000FF);
                                g.drawRect(0, 0, unscaledWidth,
unscaledHeight);
                                g.endFill();
                            }
                           
                    }else{
                        return;
                    }
                }
            }
}
}//Package

// Find complete source code in attachment.