how to detect grid view empty cell ? I need it for highlighting. So I made a css

.RedColored 
{
    background: FF0000;
}

and trying to appear it to empty GV cells this way :

protected virtual GridView1_RowDataBound (_sender : object,  e : System.Web.UI.WebControls.GridViewRowEventArgs) : void
        {
            e.Row.Cells[0].CssClass = "wide";
            foreach(i : int in [0..e.Row.Cells.Count-1])
            {
                when(e.Row.Cells[i].Text==null)
                {
                    e.Row.Cells[i].CssClass="RedColored";
                }
            }
        } 

but my it doesn't appears to empty cells , even I've tried Text=="" , Cell[i]==null, Cell[i].ToString()=="" and nothing helped.