20181101
Convert.ToDateTime(cdRQKS.EditValue).Year.ToString() +
Convert.ToDateTime(cdRQKS.EditValue).Month.ToString("00") +
Convert.ToDateTime(cdRQKS.EditValue).AddDays(1 - day).Day.ToString("00");
20181131
Convert.ToDateTime(cdRQKS.EditValue).Year.ToString() +
Convert.ToDateTime(cdRQKS.EditValue).Month.ToString("00") +
Convert.ToDateTime(cdRQKS.EditValue).AddDays(1 - day).AddMonths(1).AddDays(-1).Day.ToString("00")