Make sure that you have the start and end fields defined in your Model that you are posting back (and model inherits from ISchedulerEvent):
public class CalendarAppointmentViewModel : ISchedulerEvent
{
public int Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Recurrence { get; set; }
public string StartTimezone { get; set; }
public string EndTimezone { get; set; }
private DateTime start;
public DateTime Start
{
get
{
return start;
}
set
{
start = value.ToUniversalTime();
}
}
private DateTime end;
public DateTime End
{
get
{
return end;
}
set
{
end = value.ToUniversalTime();
}
}
public string RecurrenceRule { get; set; }
public int? RecurrenceID { get; set; }
public string RecurrenceException { get; set; }
public bool IsAllDay { get; set; }