/// <summary>
 /// 找出最大的結帳年月
 /// </summary>
 /// <returns></returns>
 public string QueryMaxYM()
 {
     try
     {
         DBO.VDM_VendorAgmDBO dbo = new VDM_VendorAgmDBO(ref USEDB);
         return dbo.QueryMaxYM();
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }