Class CalendarSystem
Inherited Members
Namespace: NodaTime
Assembly: NodaTime.dll
Syntax
public sealed class CalendarSystemRemarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Properties
Eras
Declaration
public IList<Era> Eras { get; }Property Value
| Type | Description |
|---|---|
| IList<Era> |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Id
Declaration
public string Id { get; }Property Value
| Type | Description |
|---|---|
| String |
Remarks
A unique ID for a calendar is required when serializing types which include a CalendarSystem. As of 2 Nov 2012 (ISO calendar) there are no ISO or RFC standards for naming a calendar system. As such, the identifiers provided here are specific to Noda Time, and are not guaranteed to interoperate with any other date and time API.
Ids
Declaration
public static IEnumerable<string> Ids { get; }Property Value
| Type | Description |
|---|---|
| IEnumerable<String> |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Iso
Declaration
public static CalendarSystem Iso { get; }Property Value
| Type | Description |
|---|---|
| CalendarSystem |
Remarks
When ISO does not define a field, but it can be determined (such as AM/PM) it is included.
With the exception of century related fields, the ISO calendar is exactly the same as the Gregorian calendar system. In the ISO system, centuries and year of century are zero based. For all years, the century is determined by dropping the last two digits of the year, ignoring sign. The year of century is the value of the last two year digits.
MaxYear
Declaration
public int MaxYear { get; }Property Value
| Type | Description |
|---|---|
| Int32 |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
MinYear
Declaration
public int MinYear { get; }Property Value
| Type | Description |
|---|---|
| Int32 |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Name
Declaration
public string Name { get; }Property Value
| Type | Description |
|---|---|
| String |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
UsesIsoDayOfWeek
Declaration
public bool UsesIsoDayOfWeek { get; }Property Value
| Type | Description |
|---|---|
| Boolean |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Methods
ForId(String)
Declaration
public static CalendarSystem ForId(string id)Parameters
| Type | Name | Description |
|---|---|---|
| String | id | The ID of the calendar system. This is case-sensitive. |
Returns
| Type | Description |
|---|---|
| CalendarSystem | The calendar system with the given ID. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| KeyNotFoundException | No calendar system for the specified ID can be found. |
See Also
GetAbsoluteYear(Int32, Era)
Declaration
public int GetAbsoluteYear(int yearOfEra, Era era)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | yearOfEra | The year within the era. |
| Era | era | The era in which to consider the year |
Returns
| Type | Description |
|---|---|
| Int32 | The absolute year represented by the specified year of era. |
Remarks
Exceptions
| Type | Condition |
|---|---|
| ArgumentOutOfRangeException | yearOfEra is out of the range of years for the given era. |
| ArgumentException | era is not an era used in this calendar. |
| ArgumentNullException | era is null. |
GetCopticCalendar(Int32)
Declaration
public static CalendarSystem GetCopticCalendar(int minDaysInFirstWeek)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | minDaysInFirstWeek | The minimum number of days in the first week of the year. When computing the WeekOfWeekYear and WeekYear properties of a particular date, this is used to decide at what point the week year changes. |
Returns
| Type | Description |
|---|---|
| CalendarSystem | A suitable Coptic calendar reference; the same reference may be returned by several calls as the object is immutable and thread-safe. |
Remarks
Year 1 in the Coptic calendar began on August 29, 284 CE (Julian), thus Coptic years do not begin at the same time as Julian years. This calendar is not proleptic, as it does not allow dates before the first Coptic year.
This implementation defines a day as midnight to midnight exactly as per the ISO calendar. Some references indicate that a Coptic day starts at sunset on the previous ISO day, but this has not been confirmed and is not implemented.
GetDaysInMonth(Int32, Int32)
Declaration
public int GetDaysInMonth(int year, int month)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | year | The year in which to consider the month |
| Int32 | month | The month to determine the number of days in |
Returns
| Type | Description |
|---|---|
| Int32 | The number of days in the given month and year. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| ArgumentOutOfRangeException | The given year / month combination is invalid for this calendar. |
GetGregorianCalendar(Int32)
Declaration
public static CalendarSystem GetGregorianCalendar(int minDaysInFirstWeek)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | minDaysInFirstWeek | The minimum number of days in the first week of the year. When computing the WeekOfWeekYear and WeekYear properties of a particular date, this is used to decide at what point the week year changes. |
Returns
| Type | Description |
|---|---|
| CalendarSystem | A suitable Gregorian calendar reference; the same reference may be returned by several calls as the object is immutable and thread-safe. |
Remarks
GetHebrewCalendar(HebrewMonthNumbering)
Declaration
public static CalendarSystem GetHebrewCalendar(HebrewMonthNumbering monthNumbering)Parameters
| Type | Name | Description |
|---|---|---|
| HebrewMonthNumbering | monthNumbering | The month numbering system to use |
Returns
| Type | Description |
|---|---|
| CalendarSystem | A Hebrew calendar system for the given month numbering. |
Remarks
Please note that in version 1.3.0 of Noda Time, support for the Hebrew calendar is somewhat experimental, particularly in terms of calculations involving adding or subtracting years. Additionally, text formatting and parsing using month names is not currently supported, due to the challenges of handling leap months. It is hoped that this will be improved in future versions.
The implementation for this was taken from http://www.cs.tau.ac.il/~nachum/calendar-book/papers/calendar.ps, which is a public domain algorithm presumably equivalent to that given in the Calendrical Calculations book by the same authors (Nachum Dershowitz and Edward Reingold).
GetIslamicCalendar(IslamicLeapYearPattern, IslamicEpoch)
Declaration
public static CalendarSystem GetIslamicCalendar(IslamicLeapYearPattern leapYearPattern, IslamicEpoch epoch)Parameters
| Type | Name | Description |
|---|---|---|
| IslamicLeapYearPattern | leapYearPattern | The pattern of years in the 30-year cycle to consider as leap years |
| IslamicEpoch | epoch | The kind of epoch to use (astronomical or civil) |
Returns
| Type | Description |
|---|---|
| CalendarSystem | A suitable Islamic calendar reference; the same reference may be returned by several calls as the object is immutable and thread-safe. |
Remarks
This returns a tablular calendar, rather than one based on lunar observation. This calendar is a lunar calendar with 12 months, each of 29 or 30 days, resulting in a year of 354 days (or 355 on a leap year).
Year 1 in the Islamic calendar began on July 15th or 16th, 622 CE (Julian), thus Islamic years do not begin at the same time as Julian years. This calendar is not proleptic, as it does not allow dates before the first Islamic year.
There are two basic forms of the Islamic calendar, the tabular and the observed. The observed form cannot easily be used by computers as it relies on human observation of the new moon. The tabular calendar, implemented here, is an arithmetic approximation of the observed form that follows relatively simple rules.
You should choose an epoch based on which external system you wish to be compatible with. The epoch beginning on July 16th is the more common one for the tabular calendar, so using Civil would usually be a logical choice. However, Windows uses July 15th, so if you need to be compatible with other Windows systems, you may wish to use Astronomical. The fact that the Islamic calendar traditionally starts at dusk, a Julian day traditionally starts at noon, and all calendar systems in Noda Time start their days at midnight adds somewhat inevitable confusion to the mix, unfortunately.
The tabular form of the calendar defines 12 months of alternately 30 and 29 days. The last month is extended to 30 days in a leap year. Leap years occur according to a 30 year cycle. There are four recognised patterns of leap years in the 30 year cycle:
| Origin | Leap years |
|---|---|
| Kūshyār ibn Labbān | 2, 5, 7, 10, 13, 15, 18, 21, 24, 26, 29 |
| al-Fazārī | 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, 29 |
| Fātimid (also known as Misri or Bohra) | 2, 5, 8, 10, 13, 16, 19, 21, 24, 27, 29 |
| Habash al-Hasib | 2, 5, 8, 11, 13, 16, 19, 21, 24, 27, 30 |
The leap year pattern to use is determined from the first parameter to this factory method. The second parameter determines which epoch is used - the "astronomical" or "Thursday" epoch (July 15th 622CE) or the "civil" or "Friday" epoch (July 16th 622CE).
This implementation defines a day as midnight to midnight exactly as per the ISO calendar. This correct start of day is at sunset on the previous day, however this cannot readily be modelled and has been ignored.
GetJulianCalendar(Int32)
Declaration
public static CalendarSystem GetJulianCalendar(int minDaysInFirstWeek)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | minDaysInFirstWeek | The minimum number of days in the first week of the year. When computing the WeekOfWeekYear and WeekYear properties of a particular date, this is used to decide at what point the week year changes. |
Returns
| Type | Description |
|---|---|
| CalendarSystem | A suitable Julian calendar reference; the same reference may be returned by several calls as the object is immutable and thread-safe. |
Remarks
GetMaxMonth(Int32)
Declaration
public int GetMaxMonth(int year)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | year | The year to consider. |
Returns
| Type | Description |
|---|---|
| Int32 | The maximum month number within the given year. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| ArgumentOutOfRangeException | The given year is invalid for this calendar. Note that some implementations may return a month rather than throw this exception (for example, if all years have the same number of months in this calendar system). Failure to throw an exception should not be treated as an indication that the year is valid. |
GetMaxYearOfEra(Era)
Declaration
public int GetMaxYearOfEra(Era era)Parameters
| Type | Name | Description |
|---|---|---|
| Era | era | The era in which to find the greatest year |
Returns
| Type | Description |
|---|---|
| Int32 | The maximum valid year in the given era. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| ArgumentException | era is not an era used in this calendar. |
| ArgumentNullException | era is null. |
GetMinYearOfEra(Era)
Declaration
public int GetMinYearOfEra(Era era)Parameters
| Type | Name | Description |
|---|---|---|
| Era | era | The era in which to find the greatest year |
Returns
| Type | Description |
|---|---|
| Int32 | The minimum valid year in the given eraera. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| ArgumentException | era is not an era used in this calendar. |
| ArgumentNullException | era is null. |
GetPersianCalendar()
Declaration
public static CalendarSystem GetPersianCalendar()Returns
| Type | Description |
|---|---|
| CalendarSystem | A Persian calendar system. |
Remarks
PersianCalendar class, and the dates of
this implementation align exactly with the BCL implementation.
IsLeapYear(Int32)
Declaration
public bool IsLeapYear(int year)Parameters
| Type | Name | Description |
|---|---|---|
| Int32 | year | The year to consider. |
Returns
| Type | Description |
|---|---|
| Boolean | True if the given year is a leap year; false otherwise. |
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.
Exceptions
| Type | Condition |
|---|---|
| ArgumentOutOfRangeException | The given year is invalid for this calendar. Note that some implementations may return a value rather than throw this exception. Failure to throw an exception should not be treated as an indication that the year is valid. |
ToString()
Declaration
public override string ToString()Returns
| Type | Description |
|---|---|
| String | The ID of this calendar system. |
Overrides
Remarks
Many developers will never need to touch this class, other than to potentially ask a calendar how many days are in a particular year/month and the like. Noda Time defaults to using the ISO-8601 calendar anywhere that a calendar system is required but hasn't been explicitly specified.
If you need to obtain a CalendarSystem instance, use one of the static properties or methods in this class, such as the Iso property or the GetGregorianCalendar(Int32) method.
Although this class is currently sealed (as of Noda Time 1.2), in the future this decision may be reversed. In any case, there is no current intention for third-party developers to be able to implement their own calendar systems (for various reasons). If you require a calendar system which is not currently supported, please file a feature request and we'll see what we can do.