Question

Linq

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;
}

Records time : 10/10/2012 – between 09:15 and 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)

How can I group records by week. What is the wrong about my weekly grouping?

Thanks in advance.

Answer 1

I would imagine your Date has a time part – you need to zero it out, e.g.

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