var groups = netflow.OrderByDescending(x => x).GroupBy(x => x).Select(x => x.Key).ToArray();
var rank = netflow.Select(x => Array.IndexOf(groups, x)+1);

int[] rankResult = rank;
for (int ii = 0; ii < rankResult.Length; ii++)
            {
                string empNumb = dataGridView1[dataGridView1.Columns["empNumb"].Index, ii].Value.ToString();
                RC.updateRank(rankResult[ii], empNumb, period, year);
            }