生成流水号：年月日(yyyymmdd) + 吧台号(###) + 五位流水号。共16位

//==============生成账号函数============================

 public string GetSerialNumber(string bar)

        {
            DataSet ds = new DAL.AccountInfo().Account(bar);===============取出数据库带有今天的日期的账号信息
          
            if (!Common.NullCheck.DataSetIsNull(ds))=================如果取出的不为空，则顺序增加
            {
                string serialNumber = ds.Tables[0].Rows[0]["Account_No"].ToString();
                string headDate = serialNumber.Substring(0, 8);
                int lastNumber = int.Parse(serialNumber.Substring(11,5));
                //如果数据库最大值流水号中日期和生成日期在同一天，则顺序号加1
                if (headDate == DateTime.Now.ToString("yyyyMMdd"))
                {
                    lastNumber++;
                    return headDate +bar+ lastNumber.ToString("00000");
                }

            }

          //=========如果取出的为空，则从第一个账号开始生成，一天最多可以生成99999个账号

            return DateTime.Now.ToString("yyyyMMdd") +bar+ "00001";

        }

//===================取出数据库今天的账号信息=========================

public DataSet Account(string bar)
        {
            StringBuilder sql = new StringBuilder();
            sql.AppendLine(" SELECT Top 1 * ");
            sql.AppendLine("FROM [Account_Info] AS Account_Info");
            sql.AppendLine("where Account_No like '%" + DateTime.Now.ToString("yyyyMMdd") + bar + "%'");
            sql.AppendLine("order by Account_No desc");

            DataSet ds = new DataSet();
            ds = QueryMethods.Search(sql.ToString());
            return ds;
        }