public string getProjectRepairMan(int projID) { DataTable dt = getDetailDataTableByProjID(projID); repairmanBLL rmBLL = new repairmanBLL(); if (dt.Rows.Count == 0) { return(""); } else if (dt.Rows.Count == 1) { repairmanTable rm = rmBLL.getRMinfoById(Convert.ToInt32(dt.Rows[0]["repairmanID"])); return(rm == null ? "" : rm.repairmanName); } else { List <string> rmList = dt.AsEnumerable().Select(row => row["repairmanID"].ToString()).ToList <string>(); List <string> rmNameList = new List <string>(); foreach (string rmID in rmList) { repairmanTable rm = rmBLL.getRMinfoById(Convert.ToInt32(rmID)); if (rm != null) { rmNameList.Add(rm.repairmanName); } } return(string.Join(", ", rmNameList)); } }