public static HashSet <Occurrence> GetOccurrences(IRecurrable recurrable, IDateTime periodStart, IDateTime periodEnd, bool includeReferenceDateInResults)
{
var evaluator = recurrable.GetService(typeof(IEvaluator)) as IEvaluator;
if (evaluator == null || recurrable.Start == null)
{
return(new HashSet <Occurrence>());
}
// Ensure the start time is associated with the object being queried
var start = recurrable.Start;
start.AssociatedObject = recurrable as ICalendarObject;
// Change the time zone of periodStart/periodEnd as needed
// so they can be used during the evaluation process.
periodStart.TzId = start.TzId;
periodEnd.TzId = start.TzId;
var periods = evaluator.Evaluate(start, DateUtil.GetSimpleDateTimeData(periodStart), DateUtil.GetSimpleDateTimeData(periodEnd),
includeReferenceDateInResults);
var otherOccurrences = from p in periods
let endTime = p.EndTime ?? p.StartTime
where
(endTime.GreaterThan(periodStart) && p.StartTime.LessThan(periodEnd) ||
(periodStart.Equals(periodEnd) && p.StartTime.LessThanOrEqual(periodStart) && endTime.GreaterThan(periodEnd))) || //A period that starts at the same time it ends
(p.StartTime.Equals(endTime) && periodStart.Equals(p.StartTime)) //An event that starts at the same time it ends
select new Occurrence(recurrable, p);
var occurrences = new HashSet <Occurrence>(otherOccurrences);
return(occurrences);
}
