[Solved] EXDATE in generated recurrence string is off by 4 hours

[Kevin Schneider]

if (calendarEvent.RecurrenceParent != null && calendarEvent.ExceptionDate.HasValue)
        {
            DateTime exceptionDate = calendarEvent.ExceptionDate.Value;
            RecurrenceRule rrule;

            if (RecurrenceRule.TryParse(calendarEvent.RecurrenceParent.RecurrencePattern, out rrule))
            {
                if (!rrule.Exceptions.Contains(exceptionDate))
                {
                    rrule.Exceptions.Add(exceptionDate);  // Add the exception date to the parent rule

                    calendarEvent.RecurrenceParent.RecurrencePattern = rrule.ToString();
                }
            }
        }

I'm having an issue when trying to manually add datetime values to a recurrences exception list.  Above you can see the code I'm using.

My problem is that when I use rrule.ToString() the date that is being generated for EXDATE in the resulting string is ahead by 4 hours.  The rest of the dates (DTSTART, DTEND, UNTIL) are all correct though.

Thanks for your help.

[Kevin Schneider]

I probably should have mentioned - yes I realize this is a UTC issue.  What I don't understand is why the DTSTART/DTEND values are serialized using my local values but the exceptions are serialized as UTC values.

What happens is that if my start/end date for an appointment is 3:00pm and I make an exception and change some values then the exception date added would be 7:00pm.  When the calendar draws the dates it uses my 3:00pm local time for the appointment and since that is different from the 7:00pm exception it still shows the original occurence of the appointment along side the exception.

[T. Tsonev]

Hi Kevin,

Thank you for reporting this issue. We will try to fix it in time for the next service pack. Meanwhile, you can use the following workaround:

DateTime utcExceptionDate = DateTime.SpecifyKind(exceptionDate, DateTimeKind.Utc);

Greetings,
Tsvetomir Tsonev
the Telerik team

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