日期:2014-05-20  浏览次数:20734 次

求一付款记录 实现方法!
例如:
  总额 已付 未付
  50 20 30
  50 10 20
  50 5 15
这个怎么实现,其中总额和已付分别是两个表里的字段,未付是添加的一个自定义字段,请问该怎么实现,我是用linq查出的数据,主要是方法不知道怎么实现,急求。。。。

------解决方案--------------------
思路:
var query=from t1 in table1
join t2 in table2
on t1.id equals t2.t1Id
select new{总额=t1.总额 ,已付=t2.已付,未付=t1.总额-t2.已付};
------解决方案--------------------
可不可以这样理解:假设一张订单Order,编号为order001,总额是80元,第一次付款20元,第二次付款40元,第3次付款10元,目前还余10元。

然后对应2张表。表一:订单 orders
Assembly code
订单编号    总价
order001    80

------解决方案--------------------
作为一个LINQ的新手,这样的题目很有挑战性。想了一个下午,终于想出来了,还请各位LINQ的高手进一步简化和改良,以进一步提高效率,消除冗余。

附上完整的测试代码:
C# code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace PaymentRecord
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList orders = new ArrayList();
            orders.Add(new Order { _id = 1, _total = 80M });
            orders.Add(new Order { _id = 2, _total = 100M });
            orders.Add(new Order { _id = 3, _total = 20.5M });

            ArrayList payments = new ArrayList();
            payments.Add(new Payment { _id = 1, _payment = 20M, _date = DateTime.Parse("2011/06/02") });
            payments.Add(new Payment { _id = 1, _payment = 40M, _date = DateTime.Parse("2011/06/04") });
            payments.Add(new Payment { _id = 1, _payment = 10M, _date = DateTime.Parse("2011/06/12") });
            payments.Add(new Payment { _id = 2, _payment = 30M, _date = DateTime.Parse("2011/06/08") });

            var payrecords_1 = orders.OfType<Order>()
                .GroupJoin(payments.OfType<Payment>(),
                o => o._id,
                p => p._id,
                (o, ps) => ps.DefaultIfEmpty().Select(p => new
                {
                    id = o._id,
                    total = o._total,
                    payment = (p != null) ? p._payment : 0,
                    paydate = (p != null) ? p._date : (new DateTime(0))
                }))
                    .SelectMany(r => r);

            var payrecords_2 = payrecords_1.Select(s => new
            {
                id = s.id,
                total = s.total,
                payment = s.payment,
                remain = s.total - payrecords_1.Where(p => (p.id == s.id) && (p.paydate <= s.paydate))
                .Sum(sum => sum.payment),
                paydate = s.paydate
            });

            foreach (var item in payrecords_2)
                Console.WriteLine(item);
        }

        class Order { public int _id; public decimal _total; }
        class Payment { public int _id; public decimal _payment; public DateTime _date; }
    }
}