Gets or sets the ordinal number of a day within a defined month.
A positive integer value that specifies the day number within a month.
If the recurrence pattern is defined on a monthly or yearly time basis (the RecurrenceInfo.Type property is set to the RecurrenceType.Monthly or RecurrenceType.Yearly value), the DayNumber property specifies the number of the day within a month. This is used to calculate the date on which the corresponding appointment will reoccur. The effective values for this property are 1 to 31 inclusive which correspond to the days within a month.