c# - linq每周分组？

Question

林克

from c in customerReadings
group c by new { date = GetGroupingDateKey(DateRangeType, c.ReadDate), name = c.Name } into g
select new MeterReadingsForChart
{
    ReadDate = g.Key.date,
    Name = g.Key.name,
    Value = g.Sum(y => y.Value),
    TimeInterval = DateRangeType
};

GetGroupingDateKey()

private static DateTime GetGroupingDateKey(MeterReadingsTimeIntervals DateRangeType, DateTime Date)
{
    DateTime date = new DateTime();
    switch (DateRangeType)
    {
        case MeterReadingsTimeIntervals.Hourly:
            //For Example data is betweet 10:05 - 11:05
            //DateTime offSet = Date.AddMinutes(-5);
            //date = new DateTime(offSet.Year, offSet.Month, offSet.Day, offSet.Hour, 5, 0);
            date = new DateTime(Date.Year, Date.Month, Date.Day, Date.Hour, 0, 0);
            break;
        case MeterReadingsTimeIntervals.Daily:
            date = new DateTime(Date.Year, Date.Month, Date.Day, 0, 0, 0);
            break;
        case MeterReadingsTimeIntervals.Weekly:
            date = Date.AddDays(-((7 + Date.DayOfWeek - DayOfWeek.Monday) % 7));
            break;
        case MeterReadingsTimeIntervals.Monthly:
            date = new DateTime(Date.Year, Date.Month, 1, 0, 0, 0);
            break;
        case MeterReadingsTimeIntervals.Yearly:
            date = new DateTime(Date.Year, 1, 1, 0, 0, 0);
            break;
    }

    return date;
}

记录时间：10/10/2012 - 09:15 至 10:15

Hourly groupped data count  : 2 (expected)

Daily groupped data count   : 1 (expected)

Weekly groupped data count  : 5 (group count (not expected))

Monthly groupped data count : 1 (expected)

Yearly groupped data count  : 1 (expexted)

如何按周对记录进行分组。我的每周分组有什么问题？

提前致谢。

Answer 1

我想你Date有一个时间部分 - 你需要将它归零，例如

date = Date.Date.AddDays(-((7 + Date.DayOfWeek - DayOfWeek.Monday) % 7));