System.Globalization.CalendarWeekRule Enumeration

Assembly: Mscorlib.dll
Namespace: System.Globalization
Summary
Defines different rules for determining the first week of the year.
C# Syntax:
[Serializable]
public enum CalendarWeekRule
Remarks
These calendar week rules depend on the DayOfWeek value that is designated as the first day of the week. The DateTimeFormatInfo.FirstDayOfWeek property provides the default value for a culture, but any DayOfWeek value can be specified as the first day of the week in the Calendar.GetWeekOfYear method.

The first week based on the CalendarWeekRule.FirstDay value can have one to seven days. The first week based on the CalendarWeekRule.FirstFullWeek value always has seven days. The first week based on the CalendarWeekRule.FirstFourDayWeek value can have four to seven days.

For example, in the Gregorian calendar, suppose that the first day of the year (January 1) falls on a Tuesday and the designated first day of the week is Sunday. Selecting CalendarWeekRule.FirstFullWeek defines the first Sunday (January 6) as the beginning of the first week of the year. The first five days of the year are considered part of the last week of the previous year. In contrast, selecting CalendarWeekRule.FirstFourDayWeek defines the first day of the year (January 1) as the beginning of the first week of the year because there are more than four days from January 1 to the day before the following Sunday.



Date FirstDay FirstFullWeek FirstFourDayWeek
Dec 31 Mon Last week of the previous year Last week of the previous year Last week of the previous year
Jan 1 Tue Week 1 Last week of the previous year Week 1
Jan 2 Wed Week 1 Last week of the previous year Week 1
Jan 3 Thu Week 1 Last week of the previous year Week 1
Jan 4 Fri Week 1 Last week of the previous year Week 1
Jan 5 Sat Week 1 Last week of the previous year Week 1
Jan 6 Sun Week 2 Week 1 Week 2
Jan 7 Mon Week 2 Week 1 Week 2
Jan 8 Tue Week 2 Week 1 Week 2
Jan 9 Wed Week 2 Week 1 Week 2
Jan 10 Thu Week 2 Week 1 Week 2
Jan 11 Fri Week 2 Week 1 Week 2
Jan 12 Sat Week 2 Week 1 Week 2

Suppose the first day of the year (January 1) falls on a Friday and the designated first day of the week is Sunday. Selecting CalendarWeekRule.FirstFourDayWeek defines the first Sunday (January 3) as the beginning of the first week of the year because there are fewer than four days from January 1 to the day before the following Sunday.



Date FirstDay FirstFullWeek FirstFourDayWeek
Dec 31 Thu Last week of the previous year Last week of the previous year Last week of the previous year
Jan 1 Fri Week 1 Last week of the previous year Last week of the previous year
Jan 2 Sat Week 1 Last week of the previous year Last week of the previous year
Jan 3 Sun Week 2 Week 1 Week 1
Jan 4 Mon Week 2 Week 1 Week 1
Jan 5 Tue Week 2 Week 1 Week 1
Jan 6 Wed Week 2 Week 1 Week 1
Jan 7 Thu Week 2 Week 1 Week 1
Jan 8 Fri Week 2 Week 1 Week 1
Jan 9 Sat Week 2 Week 1 Week 1
See also:
System.Globalization Namespace

System.Globalization.CalendarWeekRule Member List:

Public Fields
FirstDay Indicates that the first week of the year starts on the first day of the year and ends before the following designated first day of the week. The value is 0.
FirstFourDayWeek Indicates that the first week of the year is the first week with four or more days before the designated first day of the week. The value is 2.
FirstFullWeek Indicates that the first week of the year begins on the first occurrence of the designated first day of the week on or after the first day of the year. The value is 1.

Hierarchy:


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