public static List <PurchaseOrder> ReadAllPO() { DataTable DTpo = PurchaseDataManager.GetAllPOs(); DataTable DTpod = PurchaseDataManager.GetAllPODs(); DataTable DTgrn = PurchaseDataManager.GetAllGRNs(); DataTable DTdcl = PurchaseDataManager.GetAllDCLs(); List <PurchaseOrder> allPOs = POMap.MapPOData(DTpo, DTpod, DTgrn, DTdcl); List <PurchaseOrder> calculatedPOs = new List <PurchaseOrder>(); foreach (PurchaseOrder PO in allPOs) { PurchaseOrder po = PurchaseDataManager.CalculatePO(PO); calculatedPOs.Add(po); } HttpContext.Current.Session.Add(SessionManager.POSession, calculatedPOs); _AllPOs = calculatedPOs; return(calculatedPOs); }