public IDateTime ToTimeZone(string newTimeZone)
{
if (string.IsNullOrWhiteSpace(newTimeZone))
{
throw new ArgumentException("You must provide a valid TZID to the ToTimeZone() method", "newTimeZone");
}
if (Calendar == null)
{
throw new Exception("The iCalDateTime object must have an iCalendar associated with it in order to use TimeZones.");
}
var newDt = string.IsNullOrWhiteSpace(TzId)
? DateUtil.ToZonedDateTimeLeniently(Value, newTimeZone).ToDateTimeUtc()
: DateUtil.FromTimeZoneToTimeZone(Value, TzId, newTimeZone).ToDateTimeUtc();
return(new iCalDateTime(newDt, newTimeZone));
}
/**
* Returns a list of start dates in the specified period represented by this recur. This method includes a base date
* argument, which indicates the start of the fist occurrence of this recurrence. The base date is used to inject
* default values to return a set of dates in the correct format. For example, if the search start date (start) is
* Wed, Mar 23, 12:19PM, but the recurrence is Mon - Fri, 9:00AM - 5:00PM, the start dates returned should all be at
* 9:00AM, and not 12:19PM.
*/
private HashSet <DateTime> GetDates(IDateTime seed, DateTime periodStart, DateTime periodEnd, int maxCount, IRecurrencePattern pattern, bool includeReferenceDateInResults)
{
var dates = new HashSet <DateTime>();
var originalDate = DateUtil.GetSimpleDateTimeData(seed);
var seedCopy = DateUtil.GetSimpleDateTimeData(seed);
if (includeReferenceDateInResults)
{
dates.Add(seedCopy);
}
// optimize the start time for selecting candidates
// (only applicable where a COUNT is not specified)
if (pattern.Count == int.MinValue)
{
var incremented = seedCopy;
IncrementDate(ref incremented, pattern, pattern.Interval);
while (incremented < periodStart)
{
seedCopy = incremented;
IncrementDate(ref incremented, pattern, pattern.Interval);
}
}
var expandBehavior = RecurrenceUtil.GetExpandBehaviorList(pattern);
var invalidCandidateCount = 0;
var noCandidateIncrementCount = 0;
var candidate = DateTime.MinValue;
while ((maxCount < 0) || (dates.Count < maxCount))
{
if (pattern.Until != DateTime.MinValue && candidate != DateTime.MinValue && candidate > pattern.Until)
{
break;
}
if (periodEnd != null && candidate != DateTime.MinValue && candidate > periodEnd)
{
break;
}
if (pattern.Count >= 1 && (dates.Count + invalidCandidateCount) >= pattern.Count)
{
break;
}
var candidates = GetCandidates(seedCopy, pattern, expandBehavior);
if (candidates.Count > 0)
{
noCandidateIncrementCount = 0;
// sort candidates for identifying when UNTIL date is exceeded..
candidates.Sort();
for (var i = 0; i < candidates.Count; i++)
{
candidate = candidates[i];
// don't count candidates that occur before the original date..
if (candidate >= originalDate)
{
// candidates MAY occur before periodStart
// For example, FREQ=YEARLY;BYWEEKNO=1 could return dates
// from the previous year.
//
// candidates exclusive of periodEnd..
if (candidate >= periodEnd)
{
invalidCandidateCount++;
}
else if (pattern.Count >= 1 && (dates.Count + invalidCandidateCount) >= pattern.Count)
{
break;
}
else if (pattern.Until == DateTime.MinValue || candidate <= pattern.Until)
{
var utcCandidate = DateUtil.FromTimeZoneToTimeZone(candidate, DateUtil.GetZone(seed.TzId), DateTimeZone.Utc).ToDateTimeUtc();
if (!dates.Contains(candidate) && (pattern.Until == DateTime.MinValue || utcCandidate <= pattern.Until))
{
dates.Add(candidate);
}
}
}
}
}
else
{
noCandidateIncrementCount++;
if ((maxIncrementCount > 0) && (noCandidateIncrementCount > maxIncrementCount))
{
break;
}
}
IncrementDate(ref seedCopy, pattern, pattern.Interval);
}
// sort final list..
return(dates);
}
