public ActionResult get_CANOPBill_Amount(string fdate, string tdate, int receipts, string billtype)
        {
            PatientStatisticsDB _DB = new PatientStatisticsDB();
            OPBILLCanAmount     _RE = _DB.get_CANOPBill_Amount(fdate, tdate, receipts, billtype);
            var serializer          = new JavaScriptSerializer {
                MaxJsonLength = Int32.MaxValue
            };
            var result = new ContentResult
            {
                Content     = serializer.Serialize(new { Res = _RE ?? new OPBILLCanAmount() }),
                ContentType = "application/json"
            };

            return(result);
        }