DDay.iCal.iCalDateTime.AssociateWith C# (CSharp) Method

        public void AssociateWith(IDateTime dt)
        {
            if (AssociatedObject == null && dt.AssociatedObject != null)
                AssociatedObject = dt.AssociatedObject;
            else if (AssociatedObject != null && dt.AssociatedObject == null)
                dt.AssociatedObject = AssociatedObject;

            // If these share the same TZID, then let's see if we
            // can share the time zone observance also!
            if (TZID != null && string.Equals(TZID, dt.TZID))
            {
                if (TimeZoneObservance != null && dt.TimeZoneObservance == null)
                {
                    IDateTime normalizedDt = new iCalDateTime(TimeZoneObservance.Value.TimeZoneInfo.OffsetTo.ToUTC(dt.Value));
                    if (TimeZoneObservance.Value.Contains(normalizedDt))
                        dt.TimeZoneObservance = TimeZoneObservance;
                }
                else if (dt.TimeZoneObservance != null && TimeZoneObservance == null)
                {
                    IDateTime normalizedDt = new iCalDateTime(dt.TimeZoneObservance.Value.TimeZoneInfo.OffsetTo.ToUTC(Value));
                    if (dt.TimeZoneObservance.Value.Contains(normalizedDt))
                        TimeZoneObservance = dt.TimeZoneObservance;
                }
            }
        }

        public override IList <IPeriod> Evaluate(IDateTime referenceDate, DateTime periodStart, DateTime periodEnd, bool includeReferenceDateInResults)
        {
            // Create a recurrence pattern suitable for use during evaluation.
            IRecurrencePattern pattern = ProcessRecurrencePattern(referenceDate);

            // Enforce evaluation restrictions on the pattern.
            EnforceEvaluationRestrictions(pattern);

            Periods.Clear();
            foreach (DateTime dt in GetDates(referenceDate, periodStart, periodEnd, -1, pattern, includeReferenceDateInResults))
            {
                // Turn each resulting date/time into an IDateTime and associate it
                // with the reference date.
                IDateTime newDt = new iCalDateTime(dt, referenceDate.TZID);

                // NOTE: fixes bug #2938007 - hasTime missing
                newDt.HasTime = referenceDate.HasTime;

                newDt.AssociateWith(referenceDate);

                // Create a period from the new date/time.
                IPeriod p = new Period(newDt);

                if (!Periods.Contains(p))
                {
                    Periods.Add(p);
                }
            }

            return(Periods);
        }