public static string SerializeRecurrencePattern(DDay.iCal.IRecurrencePattern recurrencePattern)
 {
     try
     {
         var serializer = new DDay.iCal.Serialization.iCalendar.RecurrencePatternSerializer();
         return(serializer.SerializeToString(recurrencePattern));
     }
     catch (Exception ex)
     {
         log4net.LogManager.GetLogger("ASC.Calendar").Error(ex);
         return(null);
     }
 }