我还在学习LINQ并且有一项任务，我需要按四个属性对Booking对象进行分组，然后根据输入时间范围按周分组。
public class Booking
{
public string Group { get; set; }
public BookingType Type { get; set; }
public BookingStatus Status { get; set; }
public decimal Price { get; set; }
public bool Notification { get; set; }
public DateTime Date { get; set; }
}
假设我们有以下预订：
IList<Booking> Bookings = new List<Booking>
{
new Booking{Group = "Group1", Type = BookingType.Online, Status = BookingStatus.New, Price = 150, Date = new DateTime(2012,06,01)},
new Booking{Group = "Group1", Type = BookingType.Online, Status = BookingStatus.New, Price = 100, Date = new DateTime(2012,06,02)},
new Booking{Group = "Group1", Type = BookingType.Online, Status = BookingStatus.New, Price = 200, Date = new DateTime(2012,06,03)},
new Booking{Group = "Group2", Type = BookingType.Phone, Status = BookingStatus.Accepted, Price = 80, Date = new DateTime(2012,06,10)},
new Booking{Group = "Group2", Type = BookingType.Phone, Status = BookingStatus.Accepted, Price = 110, Date = new DateTime(2012,06,12)},
new Booking{Group = "Group3", Type = BookingType.Store, Status = BookingStatus.Accepted, Price = 225, Date = new DateTime(2012,06,20)},
new Booking{Group = "Group3", Type = BookingType.Store, Status = BookingStatus.Invoiced, Price = 300, Date = new DateTime(2012,06,21)},
new Booking{Group = "Group3", Type = BookingType.Store, Status = BookingStatus.Invoiced, Price = 140, Date = new DateTime(2012,06,22)},
};
这将导致最终打印输出中的以下行：
Week 22 Week 23 Week 24 Week 25 Week 26
May28-Jun3 Jun4-10 Jun11-17 Jun18-24 Jun25-Jul1
Group Type Status Cnt. Price Cnt. Price Cnt. Price Cnt. Price Cnt. Price
----------------------------------------------------------------------------------------------
Group1 Online New 3 450 0 0 0 0 0 0 0 0
Group2 Phone Accepted 0 0 1 80 1 110 0 0 0 0
Group3 Store Accepted 0 0 0 0 0 0 1 225 0 0
Group3 Store Invoiced 0 0 0 0 0 0 2 440 0 0
我创建了2个额外的类来表示一行，可以包含任意数周：
public class GroupedLine
{
public string Group { get; set; }
public BookingType Type { get; set; }
public BookingStatus Status { get; set; }
public List<WeeklyStat> WeeklyStats { get; set; }
}
public class WeeklyStat
{
public DateTime WeekStart { get; set; }
public decimal Sum { get; set; }
public int Count { get; set; }
}
如果我有以下时间段：
var DateFrom = new DateTime(2012, 05, 28);
var DateTo = new DateTime(2012, 7, 01);
首先，我需要确定统计数据中需要几周的时间：在本例中为第22-26周。
为此，我有以下代码：
var DateFrom = new DateTime(2012, 05, 28);
var DateTo = new DateTime(2012, 7, 01);
var firstWeek = GetFirstDateOfWeek(DateFrom, DayOfWeek.Monday);
IList<DateTime> weeks = new List<DateTime> { firstWeek };
while(weeks.OrderByDescending(w => w).FirstOrDefault().AddDays(7) <= DateTo)
{
weeks.Add(weeks.OrderByDescending(w => w).FirstOrDefault().AddDays(7));
}
现在，我需要一些LINQ魔术才能通过4个属性和聚合（预订数量和价格总和）进行分组。
我可以附上我明天到目前为止获得的LINQ的代码示例，因为我现在无法访问它。 对不起，很长的帖子，希望我的意思很清楚。
编辑：2012-11-07 我必须稍微修改一下这个问题，以便分组的周只包括实际拥有数据的那些周。 更新了示例输出：
May28-Jun3 Jun4-10 Jun18-24
Group Type Status Cnt. Price Cnt. Price Cnt. Price
---------------------------------------------------------------
Group1 Online New 3 450 0 0 0 0
Group2 Phone Accepted 0 0 1 80 0 0
Group3 Store Accepted 0 0 0 0 1 225
Group3 Store Invoiced 0 0 0 0 2 440
在这种情况下，在6月11日至17日和6月25日至7月1日期间没有预订，因此结果中省略了它们。
答案 0 :(得分：1)
此查询将获取所有数据
var query = from b in Bookings
where b.Date >= dateFrom && b.Date <= dateTo
group b by new { b.Group, b.Type, b.Status } into g
select new GroupedLine()
{
Group = g.Key.Group,
Type = g.Key.Type,
Status = g.Key.Status,
WeeklyStats = (from b in g
let startOfWeek = GetFirstDateOfWeek(b.Date)
group b by startOfWeek into weekGroup
orderby weekGroup.Key
select new WeeklyStat()
{
WeekStart = weekGroup.Key,
Count = weekGroup.Count(),
Sum = weekGroup.Sum(x => x.Price)
}).ToList()
};
我将UI输出留给你：）
这也将返回WeekStats所有周（如果我们在某个星期没有预订组，则为0值）：
// sequence contains start dates of all weeks
var weeks = Bookings.Select(b => GetFirstDateOfWeek(b.Date))
.Distinct().OrderBy(date => date);
var query = from b in Bookings
group b by new { b.Group, b.Type, b.Status } into bookingGroup
select new GroupedLine()
{
Group = bookingGroup.Key.Group,
Type = bookingGroup.Key.Type,
Status = bookingGroup.Key.Status,
WeeklyStats = (from w in weeks
join bg in bookingGroup
on w equals GetFirstDateOfWeek(bg.Date) into weekGroup
orderby w
select new WeeklyStat()
{
WeekStart = w,
Count = weekGroup.Count(),
Sum = weekGroup.Sum(b => b.Price)
}).ToList()
};
请注意，如果您需要日期过滤器（从，到），则需要将其应用于weeks查询和bookings查询。
答案 1 :(得分：0)
var query = Bookings.GroupBy(book => new GroupedLine()
{
Group = book.Group,
Type = book.Type,
Status = book.Status
})
.Select(group => new
{
Line = group.Key,
Dates = group.GroupBy(book => GetWeekOfYear(book.Date))
.Select(innerGroup => new
{
Week = innerGroup.Key,
Count = innerGroup.Count(),
TotalPrice = innerGroup.Sum(book => book.Price)
})
});
public static int GetWeekOfYear(DateTime date)
{
return date.DayOfYear % 7;
}
答案 2 :(得分：0)
此变体在数周内生成“空”点，没有数据：
// I group by week number, it seemed clearer to me , but you can change it
var firstWeek = cal.GetWeekOfYear(DateFrom, dfi.CalendarWeekRule, dfi.FirstDayOfWeek);
var lastWeek = cal.GetWeekOfYear(DateTo, dfi.CalendarWeekRule, dfi.FirstDayOfWeek);
var q = from b in Bookings
group b by new { b.Group, b.Type, b.Status }
into g
select new
{
Group = g.Key,
Weeks =
from x in g
select new
{
Week = cal.GetWeekOfYear(x.Date,
dfi.CalendarWeekRule,
dfi.FirstDayOfWeek),
Item = x
}
} into gw
from w in Enumerable.Range(firstWeek, lastWeek-firstWeek+1)
select new
{
gw.Group,
Week = w,
Item = from we in gw.Weeks
where we.Week == w
group we by we.Item.Group into p
select new
{
p.Key,
Sum = p.Sum (x => x.Item.Price),
Count = p.Count()
}
};