string[] columns = new string[DataTableSource.Columns.Count];

            for (int index = 0; index < DataTableSource.Columns.Count; index++)
            {
                columns[index] = DataTableSource.Columns[index].ColumnName;
            }
            //得到不重复的数据行
            DataTable dt = DataTableSource.DefaultView.ToTable(true, columns); 

            foreach (DataRow dr in dt.Rows)
            {
                DataRow[] drs = DataTableSource.Select(string.Format("编号='{0}'", dr["编号"].ToString()));
                if (drs.Length > 0)
                {
                    int num = 0;
                    foreach (DataRow row in drs)
                    {
                        num += int.Parse(row["数量"].ToString());
                    }
                    dr["数量"] = num.ToString();
                }            
            }

            dataGridView1.DataSource = dt;