Linq 按年、月和员工 ID 分组，然后总工作时间相加

Question

我正在使用此代码按年、月和employeeId 对行进行分组。

var dtrSummary = from dtr in db.DTRs
                 group dtr by new { dtr.Date.Year, dtr.Date.Month, dtr.EmployeeId } into g
                 select new
                 {
                     Year = g.Key.Year,
                     Month = g.Key.Month,
                     NoOfDays = g.Count(),
                     FullName = db.EmployeeRates.Where(e => e.Id == g.Key.EmployeeId).Select(e => e.FullName).FirstOrDefault(),

                     Time1 = // Get total hours between two datetime
                             // DateTime timein = new DateTime(year, month, day, tihh1, timm1, 0);
                             // DateTime timeout = new DateTime(year, month, day, tohh1, tomm1, 0);
                             // Timespan totalTime1 = timeout - timein;
                 };

但我不知道如何使用 linq group by 来获取总小时数，就像您在上面看到的那样。

这是我的桌子：

+----------------------------------------------------------------------+
|    Date   | Timeinhh | Timeinmm | Timeouthh | Timeoutmm | EmployeeId |
+----------------------------------------------------------------------+
| 10/1/2015 | 9        | 0        | 18        | 0         | 1          |
| 10/2/2015 | 9        | 0        | 18        | 0         | 2          |
| 10/3/2015 | 9        | 0        | 18        | 0         | 1          |
| 10/4/2015 | 9        | 0        | 18        | 0         | 2          |
+----------------------------------------------------------------------+

Answer 1

您可能希望在分组 DTR 之前计算每个小时。

var DTRs2 = db.DTRs.ToList().Select(d => new
{
    Date = d.Date,
    Hours = new DateTime(d.Date.Year, d.Date.Month, d.Date.Day, d.Timeouthh, d.Timeoutmm, 0)
                .Subtract(new DateTime(d.Date.Year, d.Date.Month, d.Date.Day, d.Timeinhh, d.Timeinmm, 0)).TotalHours,
    EmployeeId = d.EmployeeId
}).ToList();

var dtrSummary =
    (from dtr in DTRs2
     group dtr by new { dtr.Date.Year, dtr.Date.Month, dtr.EmployeeId } into g
     select new
     {
         Year = g.Key.Year,
         Month = g.Key.Month,
         NoOfDays = g.Count(),
         EmpId = g.Key.EmployeeId,
         FullName = db.EmployeeRates.Where(e => e.Id == g.Key.EmployeeId).Select(e => e.FullName).FirstOrDefault(),

         Time1 = g.Sum(dtr => dtr.Hours) // Get total hours between two datetime
     });

我还建议像这样定义另一个类/表，而不是每次都使用匿名类型：

public class DTRDetails
{
    public DTR DTR { get; set; }
    public EmployeeRate EmployeeRate { get; set; }

    public string FullName
    {
        get { return EmployeeRate.FullName; }
    }

    public int Hours
    {
        get
        {
            return (int)(new DateTime(DTR.Date.Year, DTR.Date.Month, DTR.Date.Day, DTR.Timeinhh, DTR.Timeinmm, 0)
                             .Subtract(new DateTime(DTR.Date.Year, DTR.Date.Month, DTR.Date.Day, DTR.Timeouthh, DTR.Timeoutmm, 0))).TotalHours;
        }
    }

    public int Hours2
    {
        get
        {
            // return something
        }
    }

    public int Hours3
    {
        get { return Hours - Hours2; }
    }
}