Tool Tip for GridView Header

 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
    
            if (e.Row.RowType == DataControlRowType.Header)
            {
                foreach (TableCell cell in e.Row.Cells)
                {
                    cell.Attributes.Add("title",cell.Text);
                }

            }
        }