根据从数据库中获得的另一个类属性将数据提供给类属性

我从数据库的两个表中获取数据。根据从数据库中获得的另一个类属性将数据提供给类属性

表1 - 成员：

 public List<Member> ListMembers() 
     { 
      List<Member> Members = new List<Member>(); 

      string SELECT = "SELECT * FROM Members ORDER BY Id"; 

      using (sqlConnection = new SqlConnection(sqlConnectionString_WORK)) 
      { 
       sqlConnection.Open(); 

       using (SqlCommand sqlCommand = new SqlCommand(SELECT, sqlConnection)) 
       { 
        var sqlReader = sqlCommand.ExecuteReader(); 

        while (sqlReader.Read()) 
        { 
         var member = new Member 
         { 
          Id = Convert.ToInt32(sqlReader["Id"]), 
          Name = sqlReader["Name"].ToString(), 
          Surname = sqlReader["Surname"].ToString(), 
          EntryDate = Convert.ToDateTime(sqlReader["EntryDate"]) 
         }; 

         if (member.EntryDate < DateTime.Today) 
         { 
          member.Status = Status.Unpaid.ToString(); 
         } 

         else 
         { 
          member.Status = Status.Paid.ToString(); 
         } 

         Members.Add(member); 
        } 
       } 
      } 

      return Members; 
     }

表2 - 支付方式：

 public List<Payment> ListPayments(Payment entity) 
     { 
      List<Payment> Payments = new List<Payment>(); 

      string SELECT = "SELECT * FROM Payments WHERE Id = @Id"; 

      using (sqlConnection = new SqlConnection(sqlConnectionString_WORK)) 
      { 
       sqlConnection.Open(); 

       using (SqlCommand sqlCommand = new SqlCommand(SELECT, sqlConnection)) 
       { 
        sqlCommand.Parameters.Add("@Id", SqlDbType.Int).Value = entity.Id; 

        var sqlReader = sqlCommand.ExecuteReader(); 

        while (sqlReader.Read()) 
        { 
         var payment = new Payment 
         { 
          Id = Convert.ToInt32(sqlReader["Id"]), 
          Amount = Convert.ToDecimal(sqlReader["Amount"]), 
          StartDay = Convert.ToDateTime(sqlReader["StartDay"]), 
          EndDay = Convert.ToDateTime(sqlReader["EndDay"]) 
         }; 

         Payments.Add(payment); 
        } 
       } 
      } 

      return Payments; 
     }

付款的ID等于特定的会员ID。（如果会员ID是100，他/她的所有付款将具有相同的ID 100）。

现在...在ListMembers（）我给状态“付费”和“未付”根据他们的EntryDate，但我想给他们状态根据他们的最后付款。所以，相反的：

if (member.EntryDate < DateTime.Today) 
{ 
    member.Status = Status.Unpaid.ToString(); 
}

它应该是：

if (lastPayment < DateTime.Today) // lastPayment is just a word I'm using, It's not declared anywhere, I don't know how to get that value. 
{ 
    member.Status = Status.Unpaid.ToString(); 
}

我真的失去了这里，有人可以帮我吗？我不知道该怎么办。

来源

2013-06-19 Etrit

“lastPayment”会是最近的'EndDay'吗？ –

@ColmPrunty是的。所以实际上它会是“如果（theLastEndDay Etrit

你有没有得到这个工作？ –

获取成员支付：

public List<Payment> GetMemberPaymnets(int memberId) 
    { 
     List<Payment> Payments = new List<Payment>(); 

     string SELECT = "SELECT ID,AMOUNT,STARTDAY,ENDDAY FROM Payments WHERE Id = @Id order by endday desc"; 

     using (sqlConnection = new SqlConnection(sqlConnectionString_WORK)) 
     { 
      sqlConnection.Open(); 

      using (SqlCommand sqlCommand = new SqlCommand(SELECT, sqlConnection)) 
      { 
       sqlCommand.Parameters.Add("@Id", SqlDbType.Int).Value = entity.Id; 

       var sqlReader = sqlCommand.ExecuteReader(); 

       while (sqlReader.Read()) 
       { 
        var payment = new Payment 
        { 
         Id = Convert.ToInt32(sqlReader["Id"]), 
         Amount = Convert.ToDecimal(sqlReader["Amount"]), 
         StartDay = Convert.ToDateTime(sqlReader["StartDay"]), 
         EndDay = Convert.ToDateTime(sqlReader["EndDay"]) 
        }; 

        Payments.Add(payment); 
       } 
      } 
     } 

     return Payments; 
    }

，而不是

if (member.EntryDate < DateTime.Today) 
{ 
    member.Status = Status.Unpaid.ToString(); 
}

你可以使用这样的事情

foreach(Member memeber in memeberList) 
{ 
     List<Payment> memberPayments=GetMemberPayments(member.Id); 
     //also you need to check that memberPayments.Count>0 
     if(memberPayments[0].EndDay<DateTime.Today) 
     { 
      member.Status = Status.Unpaid.ToString(); 
     } 
}

但是，如果你不需要做一些操作与会员费就可以创建数据库方法，通过成员id返回成员状态状态状态。

来源

2013-06-19 09:21:42 Frank59

你可以尝试获得最新的付款日期与Member查询。取而代之的

string SELECT = "SELECT * FROM Members ORDER BY Id";

尝试

string SELECT = "SELECT m.Id, m.Name, 
m.Surname, m.EntryDate, MAX(p.EndDay) AS EndDay FROM Members m 
JOIN Payments p ON p.Id = m.Id 
ORDER BY m.Id";

，然后替换此：

if (member.EntryDate < DateTime.Today) 
{ 
    member.Status = Status.Unpaid.ToString(); 
}

与此：

var endDate = Convert.ToDateTime(sqlReader["EndDay"]) 
if (endDate < DateTime.Today) 
{ 
    member.Status = Status.Unpaid.ToString(); 
}

这是假设总是会有一个一个支付会员。如果可能有会员没有付款，则必须进行空检查和左连接。

来源

2013-06-19 09:39:45

根据从数据库中获得的另一个类属性将数据提供给类属性

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