NotableDateOnlyExtensions Class

Definition

Namespace

Bodu.Extensions

Assembly

Bodu.Globalization.Calendar.dll

Package

Bodu.Globalization.Calendar 1.0.1

Source

NotableDateOnlyExtensions.AddWorkingDays.cs

Provides working-day, traversal, and notable-date query extension methods over DateOnly, resolved through an explicit INotableDateService for a requested territory.

public static class NotableDateOnlyExtensions

Inheritance

object

NotableDateOnlyExtensions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");
DateOnly date = new(2026, 7, 3); // Friday, observed Independence Day in the US

// Is this a working day?
bool working = date.IsWorkingDay(service, "US"); // false

// Settlement date three working days out, skipping weekends and holidays.
DateOnly settles = date.AddWorkingDays(3, service, "US");

// The next working day on or after a candidate date.
DateOnly resume = date.SnapToWorkingDay(service, "US");

// Every notable date in July 2026.
IReadOnlyList<NotableDate> july = date.GetNotableDatesInMonth(service, "US");

Remarks

A working day is a day that is neither outside the working week nor a non-working notable date. The working week defaults to Monday through Friday and can be overridden with a WeekPattern. The traversal and counting methods resolve each candidate day through the service, so prefer the range-based EnumerateNotableDates(DateOnly, DateOnly, INotableDateService, string, NotableDateFilter?) for large windows.

Method groups. IsWeekend / IsWorkingDay / IsNonWorkingDay / IsNotableDate test a single day; NextWorkingDay / PreviousWorkingDay / SnapToWorkingDay (and the NonWorkingDay / NotableDate variants) traverse to a nearby day; AddWorkingDays / WorkingDaysBetween count working days; and EnumerateWorkingDays / EnumerateNonWorkingDays / EnumerateNotableDates stream a window.

Methods

AddWorkingDays(DateOnly, int, INotableDateService, string, WeekPattern?)

Advances the date by a signed number of working days.

public static DateOnly AddWorkingDays(this DateOnly date, int count, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The starting date.

count int

The number of working days to add; negative retreats, zero returns the date unchanged.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The resulting date.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// A T+2 settlement date that skips weekends and US holidays.
DateOnly trade = new(2026, 7, 2);
DateOnly settles = trade.AddWorkingDays(2, service, "US"); // jumps past July 4th observance

Exceptions

ArgumentNullException

service or territory is null.

EnumerateNonWorkingDays(DateOnly, DateOnly, INotableDateService, string, WeekPattern?)

Lazily enumerates the non-working days in the inclusive range, in ascending order.

public static IEnumerable<DateOnly> EnumerateNonWorkingDays(this DateOnly start, DateOnly end, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

start DateOnly

The inclusive start date.

end DateOnly

The inclusive end date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

IEnumerable<DateOnly>

The non-working days in the range.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// Anzac week 2024: the weekend plus Anzac Day (Thursday 25 April).
foreach (DateOnly closed in new DateOnly(2024, 4, 22).EnumerateNonWorkingDays(
    new DateOnly(2024, 4, 28), service, "AU"))
{
    // 2024-04-25, 2024-04-27, 2024-04-28
}

Exceptions

ArgumentNullException

service or territory is null.

EnumerateNotableDates(DateOnly, DateOnly, INotableDateService, string, NotableDateFilter?)

Resolves the notable dates emitted within the inclusive range for the territory.

public static IReadOnlyList<NotableDate> EnumerateNotableDates(this DateOnly start, DateOnly end, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

start DateOnly

The inclusive start date.

end DateOnly

The inclusive end date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrences must satisfy.

Returns

IReadOnlyList<NotableDate>

The emitted occurrences, ordered by date then identity.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// Every public holiday in January 2026, eagerly materialized.
IReadOnlyList<NotableDate> january = new DateOnly(2026, 1, 1).EnumerateNotableDates(
    new DateOnly(2026, 1, 31), service, "AU",
    NotableDateFilter.ForCategory(NotableDateCategory.PublicHoliday));

Exceptions

ArgumentNullException

service or territory is null.

EnumerateWorkingDays(DateOnly, DateOnly, INotableDateService, string, WeekPattern?)

Lazily enumerates the working days in the inclusive range, in ascending order.

public static IEnumerable<DateOnly> EnumerateWorkingDays(this DateOnly start, DateOnly end, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

start DateOnly

The inclusive start date.

end DateOnly

The inclusive end date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

IEnumerable<DateOnly>

The working days in the range.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// Iterate the working days of July 2026, skipping weekends and holidays.
foreach (DateOnly day in new DateOnly(2026, 7, 1).EnumerateWorkingDays(new DateOnly(2026, 7, 31), service, "US"))
    Console.WriteLine(day);

Exceptions

ArgumentNullException

service or territory is null.

GetNotableDates(DateOnly, INotableDateService, string, NotableDateFilter?)

Gets the notable dates emitted on the date for the territory.

public static IReadOnlyList<NotableDate> GetNotableDates(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

The date to resolve.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrences must satisfy.

Returns

IReadOnlyList<NotableDate>

The emitted occurrences; empty when there are none.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

IReadOnlyList<NotableDate> occurrences = new DateOnly(2026, 12, 25).GetNotableDates(service, "US");
foreach (NotableDate notable in occurrences)
    Console.WriteLine(notable.DisplayName);

Exceptions

ArgumentNullException

service or territory is null.

GetNotableDatesInMonth(DateOnly, INotableDateService, string, NotableDateFilter?)

Resolves the notable dates emitted in the calendar month that contains the date for the territory.

public static IReadOnlyList<NotableDate> GetNotableDatesInMonth(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

A date within the month to resolve.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrences must satisfy.

Returns

IReadOnlyList<NotableDate>

The emitted occurrences in the month, ordered by date then identity.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// Every notable date in December 2026, derived from any date within the month.
IReadOnlyList<NotableDate> month = new DateOnly(2026, 12, 15).GetNotableDatesInMonth(service, "US");

Exceptions

ArgumentNullException

service or territory is null.

GetNotableDatesInYear(DateOnly, INotableDateService, string, NotableDateFilter?)

Resolves the notable dates emitted in the calendar year that contains the date for the territory.

public static IReadOnlyList<NotableDate> GetNotableDatesInYear(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

A date within the year to resolve.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrences must satisfy.

Returns

IReadOnlyList<NotableDate>

The emitted occurrences in the year, ordered by date then identity.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// Every notable date in 2026, derived from any date within the year.
IReadOnlyList<NotableDate> year = new DateOnly(2026, 1, 1).GetNotableDatesInYear(service, "US");

Exceptions

ArgumentNullException

service or territory is null.

IsNonWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Determines whether the date is a non-working day: outside the working week, or a non-working notable date.

public static bool IsNonWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to test.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

bool

true if the date is non-working; otherwise false.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

bool anzacDay = new DateOnly(2024, 4, 25).IsNonWorkingDay(service, "AU");   // true (public holiday)
bool friday = new DateOnly(2024, 4, 26).IsNonWorkingDay(service, "AU");     // false

Exceptions

ArgumentNullException

service or territory is null.

IsNotableDate(DateOnly, INotableDateService, string, NotableDateFilter?)

Determines whether any notable date is emitted on the date for the territory.

public static bool IsNotableDate(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

The date to test.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrence must satisfy.

Returns

bool

true if at least one occurrence is emitted; otherwise false.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

bool isHoliday = new DateOnly(2026, 7, 4).IsNotableDate(service, "US"); // true (Independence Day)

Exceptions

ArgumentNullException

service or territory is null.

IsWeekend(DateOnly, WeekPattern?)

Determines whether the date falls outside the working week.

public static bool IsWeekend(this DateOnly date, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to test.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

bool

true if the date is not a working-week day; otherwise false.

Examples

bool saturday = new DateOnly(2026, 1, 3).IsWeekend();   // true under the default Mon-Fri week

// A Sunday-Thursday working week makes Friday the weekend instead.
var sundayToThursday = new WeekPattern(
    DayOfWeek.Sunday, DayOfWeek.Monday, DayOfWeek.Tuesday, DayOfWeek.Wednesday, DayOfWeek.Thursday);
bool friday = new DateOnly(2026, 1, 2).IsWeekend(sundayToThursday);   // true

IsWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Determines whether the date is a working day.

public static bool IsWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to test.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

bool

true if the date is a working day; otherwise false.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

bool labourDay = new DateOnly(2026, 9, 7).IsWorkingDay(service, "US");   // false (Labor Day)
bool ordinary = new DateOnly(2026, 9, 8).IsWorkingDay(service, "US");    // true

Exceptions

ArgumentNullException

service or territory is null.

NextNonWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the first non-working day strictly after the date.

public static DateOnly NextNonWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The starting date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The next non-working day.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// From Monday 22 April 2024 the next closed day is Anzac Day, before the weekend.
DateOnly closed = new DateOnly(2024, 4, 22).NextNonWorkingDay(service, "AU");   // 2024-04-25

Exceptions

ArgumentNullException

service or territory is null.

InvalidOperationException

No non-working day is found within the traversal guard.

NextNotableDate(DateOnly, INotableDateService, string, NotableDateFilter?)

Returns the earliest notable date emitted strictly after the date for the territory.

public static NotableDate? NextNotableDate(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

The reference date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrence must satisfy.

Returns

NotableDate

The next matching occurrence, or null when none exists up to the maximum year.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// The next public holiday after today.
NotableDate? upcoming = DateOnly.FromDateTime(DateTime.Today).NextNotableDate(service, "US");
if (upcoming is not null)
    Console.WriteLine($"{upcoming.DisplayName} on {upcoming.Date}");

Exceptions

ArgumentNullException

service or territory is null.

NextWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the first working day strictly after the date.

public static DateOnly NextWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The starting date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The next working day.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// The first business day after a holiday weekend.
DateOnly resume = new DateOnly(2026, 7, 3).NextWorkingDay(service, "US");

Exceptions

ArgumentNullException

service or territory is null.

PreviousNonWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the first non-working day strictly before the date.

public static DateOnly PreviousNonWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The starting date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The previous non-working day.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// From Monday 29 April 2024 the most recent closed day is the Sunday before.
DateOnly closed = new DateOnly(2024, 4, 29).PreviousNonWorkingDay(service, "AU");   // 2024-04-28

Exceptions

ArgumentNullException

service or territory is null.

InvalidOperationException

No non-working day is found within the traversal guard.

PreviousNotableDate(DateOnly, INotableDateService, string, NotableDateFilter?)

Returns the most recent notable date emitted strictly before the date for the territory.

public static NotableDate? PreviousNotableDate(this DateOnly date, INotableDateService service, string territory, NotableDateFilter? filter = null)

Parameters

date DateOnly

The reference date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

filter NotableDateFilter

An optional filter the occurrence must satisfy.

Returns

NotableDate

The previous matching occurrence, or null when none exists down to the minimum year.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// The most recent public holiday before 1 May 2024 is Anzac Day.
NotableDate? previous = new DateOnly(2024, 5, 1).PreviousNotableDate(
    service, "AU", NotableDateFilter.ForCategory(NotableDateCategory.PublicHoliday));
// previous?.Date == 2024-04-25

Exceptions

ArgumentNullException

service or territory is null.

PreviousWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the first working day strictly before the date.

public static DateOnly PreviousWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The starting date.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The previous working day.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// From Friday 26 April 2024 the previous open day skips Anzac Day back to Wednesday.
DateOnly open = new DateOnly(2024, 4, 26).PreviousWorkingDay(service, "AU");   // 2024-04-24

Exceptions

ArgumentNullException

service or territory is null.

SnapToNearestWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the date if it is a working day; otherwise the nearest working day, preferring the forward direction on a tie.

public static DateOnly SnapToNearestWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to snap.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The nearest working day.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// Saturday 27 April 2024 snaps back to Friday (one day) rather than forward to Monday (two).
DateOnly nearest = new DateOnly(2024, 4, 27).SnapToNearestWorkingDay(service, "AU");   // 2024-04-26

// A working day is returned unchanged.
DateOnly noOp = new DateOnly(2024, 4, 23).SnapToNearestWorkingDay(service, "AU");      // 2024-04-23

Exceptions

ArgumentNullException

service or territory is null.

SnapToWorkingDay(DateOnly, INotableDateService, string, WeekPattern?)

Returns the date if it is a working day; otherwise the next working day.

public static DateOnly SnapToWorkingDay(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to snap.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The date or the next working day.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// Roll a scheduled due date forward to the next working day when it lands on a holiday.
DateOnly due = new DateOnly(2026, 7, 4).SnapToWorkingDay(service, "US");

Exceptions

ArgumentNullException

service or territory is null.

SnapToWorkingDayBackward(DateOnly, INotableDateService, string, WeekPattern?)

Returns the date if it is a working day; otherwise the previous working day.

public static DateOnly SnapToWorkingDayBackward(this DateOnly date, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

date DateOnly

The date to snap.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

DateOnly

The date or the previous working day.

Examples

INotableDateService service = AsiaPacificCalendarData.CreateService("AU");

// A "no later than" contractual date falling on Anzac Day rolls back to Wednesday.
DateOnly payday = new DateOnly(2024, 4, 25).SnapToWorkingDayBackward(service, "AU");   // 2024-04-24

Exceptions

ArgumentNullException

service or territory is null.

WorkingDaysBetween(DateOnly, DateOnly, INotableDateService, string, WeekPattern?)

Counts the working days in the inclusive range bounded by the two dates, regardless of their order.

public static int WorkingDaysBetween(this DateOnly start, DateOnly end, INotableDateService service, string territory, WeekPattern? workingWeek = null)

Parameters

start DateOnly

One end of the range.

end DateOnly

The other end of the range.

service INotableDateService

The service used to resolve notable dates.

territory string

The requested territory code.

workingWeek WeekPattern?

The working-week pattern, or null for Monday to Friday.

Returns

int

The number of working days in the inclusive range.

Examples

INotableDateService service = AmericasCalendarData.CreateService("US");

// Billable working days across a project window, excluding weekends and holidays.
int days = new DateOnly(2026, 7, 1).WorkingDaysBetween(new DateOnly(2026, 7, 31), service, "US");

Exceptions

ArgumentNullException

service or territory is null.

Applies to

Product	Versions
.NET	8, 10

See Also

INotableDateService

NotableDate

NotableDateFilter

WeekPattern

Working-day arithmetic (guide)