代码坏味道特别篇————Long parameter List 过长的参数列表

刚开始学习编程时，老师说：讲方法所需要的东西都以参数的形式传入，那是我们好像还没学OO这个东东，要不就弄成全局变量，我擦，全局变量可牛逼了，刚开始学习的时候我们都在用全局变量，可是后来工作了，经理说不要用全局变量，我当时就有些醉了，突然间觉得就不会写代码了，其实我们可以用对象来解决这个问题，这样我们就不会开到过长的参数列表了

     private DataTable getSentInfo(string Pno, string Pname, string Psytle, string SentTime,string DealerNo,string DealerName)
     {
         string sqlStr = "select convert(decimal(18,2),round(sum(sc.Price*srd.SentNum ),2))as countPrice,sum(srd.SentNum) as num "
             + "from  LB_Sent_Rec sr inner join LB_Sent_RecDetail srd "
            + "on sr.SentID=srd.SentID inner join LB_Sale_Rec sc "
            + "on sc.SaleID=srd.SaleID where sc.cid='" + cidH.Value + "' and sc.Pno='" + Pno + "' and sc.Pname='" + Pname + "' and sc.PStyle='" + Psytle + "' "
            + "and sc.DealerNo='" + DealerNo + "' and sc.DealerName='" + DealerName + "' "
            + "and sr.SentTime between '" + SentTime + " 00:00:00' and '" + SentTime + " 23:59:59'";
         return DbHelperSQL.GetDataTable(sqlStr);
     }

使用对象后的代码

 public class Product
 {
     public Product()
     {
         //
         //TODO: 在此处添加构造函数逻辑
         //
     }

     public string Pno { get; set; }
     public string Pnamr { get; set; }
     public string Psytle { get; set; }
     public string SentTime { get; set; }
     public string DealerNo{get;set;}
     public string DealerName { get; set; }
 }

  private DataTable getSentInfo(Product pr)
     {
     string  sqlStr = "select convert(decimal(18,2),round(sum(sc.Price*srd.SentNum ),2))as countPrice,sum(srd.SentNum) as num "
             + "from  LB_Sent_Rec sr inner join LB_Sent_RecDetail srd "
            + "on sr.SentID=srd.SentID inner join LB_Sale_Rec sc "
            + "on sc.SaleID=srd.SaleID where sc.cid='" + cidH.Value + "' and sc.Pno='" + pr.Pno + "' and sc.Pname='" + pr.Pnamr + "' and sc.PStyle='" + pr.Psytle + "' "
            + "and sc.DealerNo='" + pr.DealerNo + "' and sc.DealerName='" + pr.DealerName + "' "
            + "and sr.SentTime between '" + pr.SentTime + " 00:00:00' and '" + pr.SentTime + " 23:59:59'";
         return DbHelperSQL.GetDataTable(sqlStr);
     }

这样是不是更容易理解传入参数所表示的内容呢？

这种方法书中叫 introduce Parameter Object