这是我的问题： 我必须将两个月收入之间的所有条目加起来，并使用相同的参考。 示例：
Month 1
Payment Date Ref Amount
03/11/2018 donations1 £ 10
05/11/2018 donations2 £ 90
07/11/2018 donations3 £ 100
01/11/2018 Gift Aid £ 200 (Needs to be the sum of donations)
11/11/2018 donation4 £ 30
12/11/2018 donations5 £ 20
10/11/2018 Gift Aid £ 50 (Needs to be the sum of donations)
在所有捐赠之间，捐赠（1,2,3）的总和必须等于所有捐赠及其全年的后续输入，以便显示全年报告。 如何使用C＃中的 LINQ 执行此操作？ 我正在使用MVC方法。
从Gufus提取的代码已调整为我的代码（非常有用！），但仍然不是我想要的。
var listGaDonations = db.Upload
.Where(x => x.IsGiftAid == true)
.ToList();
var list = from e in listGaDonations
where e.FirstName != "Gift Aid"
group e.Amount by e.Ref
into p
select new
{
Ref = p.Key,
Amount = p.Sum()
};
var listJoined = from p in list
join e in listGaDonations on p.Ref equals e.Ref
group e.PaymentDate by p
into a
select new
{
a.Key.Ref,
a.Key.Amount,
PaymentDate = a.Max()
};
foreach (var p in listJoined)
{
Upload e = new Upload(p.Ref, "Gift Aid", p.PaymentDate, p.Amount);
listGaDonations.Add(e);
}
var sortentries = from e in listGaDonations
orderby e.Ref, e.PaymentDate
select e;
var test = sortentries.Where(x => x.PaymentDate != DateTime.MinValue).ToList();
return View(test);
我得到的结果：
Ref: Donation Payment Date Amount
CIZ3S42J don1 19/08/2018 £100.00
EG066AUM don2 01/08/2018 £123.00
EUGOP7T9 don3 04/09/2018 £55.00
GRMEV47F Gift Aid 02/09/2018 £xxx (Which is not the sum of
donations)
有人可以帮助我，提前感谢您的支持。
答案 0 :(得分：0)
我试图解释您的指示，所以我认为您必须以这种方式或多或少地定义条目的类别
public class Entry
{
private int _reference;
private string _donation;
private DateTime _date;
private double _amount;
public Entry(int aReference, string aDonation, DateTime aDate, double aAmount)
{
_reference = aReference;
_donation = aDonation;
_date = aDate;
_amount = aAmount;
}
public double Amount
{
get { return _amount; }
set { _amount = value; }
}
public DateTime Date
{
get { return _date; }
set { _date = value; }
}
public string Donation
{
get { return _donation; }
set { _donation = value; }
}
public int Reference
{
get { return _reference; }
set { _reference = value; }
}
}
我敢肯定会有更聪明的编写程序的方法，但是以下方法似乎可行
List<Entry> entries = new List<Entry>();
entries.Add(new Entry(1, "donation 1", new DateTime(2018, 11, 3), 10));
entries.Add(new Entry(1, "donation 2", new DateTime(2018, 11, 5), 90));
entries.Add(new Entry(1, "donation 3", new DateTime(2018, 11, 7), 100));
entries.Add(new Entry(2, "donation 4", new DateTime(2018, 11, 11), 30));
entries.Add(new Entry(2, "donation 5", new DateTime(2018, 11, 12), 20));
var list = from e in entries
where e.Donation != "partial total"
group e.Amount by e.Reference into p
select new
{
Reference = p.Key,
Amount = p.Sum()
};
var listjoined = from p in list
join e in entries on p.Reference equals e.Reference
group e.Date by p into a
select new
{
Reference = a.Key.Reference,
Amount = a.Key.Amount,
Date = a.Max()
};
foreach(var p in listjoined)
{
Entry e = new Entry(p.Reference, "partial total", p.Date, p.Amount);
entries.Add(e);
}
var sortedentries = from e in entries
orderby e.Reference, e.Date
select e;
foreach(var e in sortedentries)
{
Console.WriteLine($"{e.Reference}; {e.Donation} occurred on {e.Date}; the amount is of {e.Amount} USD");
}
如果您希望按月总计，则只需在其中仅保留部分总计（或丢弃它们并进行单次捐赠：您只需确保避免重复计算）的地方放一个where子句，然后将金额分组即可月日期（这与我在列表中所做的操作类似）。
答案 1 :(得分：0)
新版本；我的假设是，一开始您就没有“赠金”记录。
我修改了Entry类，只是更改了Reference（它是字符串而不是int）
public class Entry
{
private string _reference;
private string _donation;
private DateTime _date;
private double _amount;
public Entry(string aReference, string aDonation, DateTime aDate, double aAmount)
{
_reference = aReference;
_donation = aDonation;
_date = aDate;
_amount = aAmount;
}
public double Amount
{
get { return _amount; }
set { _amount = value; }
}
public DateTime Date
{
get { return _date; }
set { _date = value; }
}
public string Donation
{
get { return _donation; }
set { _donation = value; }
}
public string Reference
{
get { return _reference; }
set { _reference = value; }
}
}
我添加了一个从Entry派生的类，即Entry2：
public class Entry2:Entry
{
private DateTime _date2;
public Entry2(string aReference, string aDonation, DateTime aDate, double aAmount, DateTime aDate2)
:base(aReference, aDonation, aDate, aAmount)
{
_date2 = aDate2;
}
public DateTime Date2
{
get { return _date2; }
set { _date2 = value; }
}
}
Entry2的DateTime字段多于Entry；您的数据采用Entry的形式，我将它们转换为Entry2对象，在其中添加的参数按照对象Entry中的DateTime的以下星期日进行了赋值。要分配此值，我使用了以下功能
public static DateTime NextSunday(DateTime aDate)
{
if (aDate.DayOfWeek.ToString() == "Monday") { return aDate.AddDays(6); }
else if (aDate.DayOfWeek.ToString() == "Tuesday") { return aDate.AddDays(5); }
else if (aDate.DayOfWeek.ToString() == "Wednesday") { return aDate.AddDays(4); }
else if (aDate.DayOfWeek.ToString() == "Thursday") { return aDate.AddDays(3); }
else if (aDate.DayOfWeek.ToString() == "Friday") { return aDate.AddDays(2); }
else if (aDate.DayOfWeek.ToString() == "Saturday") { return aDate.AddDays(1); }
else { return aDate; }
}
最后...程序！您可以看到我按新的DateTime字段分组。只有两个查询（而不是两个），因为现在我不需要计算与关联到各个捐赠的“礼物援助”条目关联的日期，因为现在我是使用NextSunday方法开始构建的
List<Entry> entries = new List<Entry>();
entries.Add(new Entry("d1", "donation 1", new DateTime(2018, 11, 3), 10));
entries.Add(new Entry("d2", "donation 2", new DateTime(2018, 11, 5), 90));
entries.Add(new Entry("d3", "donation 3", new DateTime(2018, 11, 7), 100));
entries.Add(new Entry("d4", "donation 4", new DateTime(2018, 11, 11), 30));
entries.Add(new Entry("d5", "donation 5", new DateTime(2018, 11, 12), 20));
List<Entry2> entries2 = new List<Entry2>();
foreach(var e in entries)
{
entries2.Add(new Entry2(e.Reference, e.Donation, e.Date, e.Amount, NextSunday(e.Date)));
}
var list = from e in entries2
where e.Donation != "Gift Aid"
group e.Amount by e.Date2 into p
select new
{
Date2 = p.Key,
Amount = p.Sum()
};
foreach(var p in list)
{
Entry e = new Entry("Some code", "Gift Aid", p.Date2, p.Amount);
entries.Add(e);
}
var sortedentries = from e in entries
orderby e.Date
select e;
foreach(var e in sortedentries)
{
Console.WriteLine($"{e.Reference}; {e.Donation} occurred on {e.Date}; the amount is of {e.Amount} USD");
}
我再说一遍，我认为这可能是非常相关的：我已经在评论中问过您有关此方面的信息，但您从未问过我。金额的类型可能还有一个问题：您的数据中是数字吗？如果是字符串，则求和可能会遇到问题...
程序的结果与您的示例不同，因为11月3日，5月7日和7月7日不在同一周，这就是为什么3个单独存在而3、5的数量相加的原因（还有11/11的数量，因为在3和5的同一周）。
希望有帮助！