Struct YearMonth

A year and month in a particular calendar. This is effectively LocalDate without the day-of-month component.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Implements

IEquatable<YearMonth>

IComparable<YearMonth>

IComparable

IFormattable

IXmlSerializable

IComparisonOperators<YearMonth, YearMonth, bool>

IEqualityOperators<YearMonth, YearMonth, bool>

Inherited Members

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: NodaTime

Assembly: NodaTime.dll

Syntax

[TypeConverter(typeof(YearMonthTypeConverter))]
public struct YearMonth : IEquatable<YearMonth>, IComparable<YearMonth>, IComparable, IFormattable, IXmlSerializable, IComparisonOperators<YearMonth, YearMonth, bool>, IEqualityOperators<YearMonth, YearMonth, bool>

Remarks

Values can freely be compared for equality: a value in a different calendar system is not equal to a value in a different calendar system. However, ordering comparisons fail with ArgumentException; attempting to compare values in different calendars almost always indicates a bug in the calling code.

Constructors

YearMonth(Era, int, int)

Constructs an instance for the given era, year of era and month in the ISO calendar.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public YearMonth(Era era, int yearOfEra, int month)

Parameters

Type	Name	Description
Era	era	The era within which to create a year/month. Must be a valid era within the ISO calendar.
int	yearOfEra	The year of era.
int	month	The month of year.

Sample snippet

using NodaTime;
using NodaTime.Calendars;
using System;

YearMonth yearMonth = new YearMonth(Era.Common, 1994, 5);
Console.WriteLine(yearMonth.Year);
Console.WriteLine(yearMonth.Month);
Console.WriteLine(yearMonth.Calendar);
Console.WriteLine(yearMonth.Era);

Output:

1994
5
ISO
CE

Exceptions

Type	Condition
ArgumentOutOfRangeException	The parameters do not form a valid year/month.

YearMonth(Era, int, int, CalendarSystem)

Constructs an instance for the given era, year of era and month in the specified calendar.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public YearMonth(Era era, int yearOfEra, int month, CalendarSystem calendar)

Parameters

Type	Name	Description
Era	era	The era within which to create a year/month. Must be a valid era within the specified calendar.
int	yearOfEra	The year of era.
int	month	The month of year.
CalendarSystem	calendar	Calendar system in which to create the year/month.

Sample snippet

using NodaTime;
using NodaTime.Calendars;
using System;

YearMonth yearMonth = new YearMonth(Era.Common, 2019, 5, CalendarSystem.Gregorian);
Console.WriteLine(yearMonth.Year);
Console.WriteLine(yearMonth.Month);
Console.WriteLine(yearMonth.Calendar);
Console.WriteLine(yearMonth.Era);

Output:

2019
5
Gregorian
CE

Exceptions

Type	Condition
ArgumentOutOfRangeException	The parameters do not form a valid year/month.

YearMonth(int, int)

Constructs an instance for the given year and month in the ISO calendar.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public YearMonth(int year, int month)

Parameters

Type	Name	Description
int	year	The year. This is the "absolute year", so a value of 0 means 1 BC, for example.
int	month	The month of year.

Sample snippet

using NodaTime;
using System;

YearMonth yearMonth = new YearMonth(2019, 5);
Console.WriteLine(yearMonth.Year);
Console.WriteLine(yearMonth.Month);
Console.WriteLine(yearMonth.Calendar);

Output:

2019
5
ISO

Exceptions

Type	Condition
ArgumentOutOfRangeException	The parameters do not form a valid year/month.

YearMonth(int, int, CalendarSystem)

Constructs an instance for the given year and month in the specified calendar.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public YearMonth(int year, int month, CalendarSystem calendar)

Parameters

Type	Name	Description
int	year	The year. This is the "absolute year", so, for the ISO calendar, a value of 0 means 1 BC, for example.
int	month	The month of year.
CalendarSystem	calendar	Calendar system in which to create the year/month.

Sample snippet

using NodaTime;
using System;

YearMonth yearMonth = new YearMonth(2014, 3, CalendarSystem.Julian);
Console.WriteLine(yearMonth.Year);
Console.WriteLine(yearMonth.Month);
Console.WriteLine(yearMonth.Calendar);

Output:

2014
3
Julian

Exceptions

Type	Condition
ArgumentOutOfRangeException	The parameters do not form a valid year/month.

Properties

Calendar

Gets the calendar system associated with this year/month.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public CalendarSystem Calendar { get; }

Property Value

Type	Description
CalendarSystem	The calendar system associated with this year/month.

Era

Gets the era of this year/month.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public Era Era { get; }

Property Value

Type	Description
Era	The era of this year/month.

Month

Gets the month of this year/month within the year.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public int Month { get; }

Property Value

Type	Description
int	The month of this year/month within the year.

Year

Gets the year of this year/month.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public int Year { get; }

Property Value

Type	Description
int	The year of this year/month.

Remarks

This returns the "absolute year", so, for the ISO calendar, a value of 0 means 1 BC, for example.

YearOfEra

Gets the year of this value within the era.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public int YearOfEra { get; }

Property Value

Type	Description
int	The year of this value within the era.

Methods

AddSchema(XmlSchemaSet)

Adds the XML schema type describing the structure of the YearMonth XML serialization to the given xmlSchemaSet.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static XmlQualifiedName AddSchema(XmlSchemaSet xmlSchemaSet)

Parameters

Type	Name	Description
XmlSchemaSet	xmlSchemaSet	The XML schema set provided by XmlSchemaExporter.

Returns

Type	Description
XmlQualifiedName	The qualified name of the schema type that was added to the xmlSchemaSet.

CompareTo(YearMonth)

Indicates whether this year/month is earlier, later or the same as another one. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public int CompareTo(YearMonth other)

Parameters

Type	Name	Description
YearMonth	other	The other year/month to compare this one with

Returns

Type	Description
int	A value less than zero if this year/month is earlier than other; zero if this year/month is the same as other; a value greater than zero if this date is later than other.

Exceptions

Type	Condition
ArgumentException	The calendar system of other is not the same as the calendar system of this value.

Equals(YearMonth)

Compares two YearMonth values for equality. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public bool Equals(YearMonth other)

Parameters

Type	Name	Description
YearMonth	other	The value to compare this year/month with.

Returns

Type	Description
bool	True if the given value is another year/month equal to this one; false otherwise.

Equals(object?)

Compares two YearMonth values for equality. See the type documentation for a description of equality semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public override bool Equals(object? obj)

Parameters

Type	Name	Description
object	obj	The object to compare this year/month with.

Returns

Type	Description
bool	True if the given value is another year/month equal to this one; false otherwise.

Overrides

ValueType.Equals(object)

GetHashCode()

Returns a hash code for this year/month. See the type documentation for a description of equality semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public override int GetHashCode()

Returns

Type	Description
int	A hash code for this value.

Overrides

ValueType.GetHashCode()

OnDayOfMonth(int)

Returns a LocalDate with the year/month of this value, and the given day of month.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public LocalDate OnDayOfMonth(int day)

Parameters

Type	Name	Description
int	day	The day within the month.

Returns

Type	Description
LocalDate	The result of combining this year and month with day.

Exceptions

Type	Condition
ArgumentOutOfRangeException	day does not fall within the month represented by this value.

PlusMonths(int)

Returns a YearMonth object which is the result of adding the specified number of months to this object.

Since 3.1.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public YearMonth PlusMonths(int months)

Parameters

Type	Name	Description
int	months	The number of months to add to this object.

Returns

Type	Description
YearMonth	The resulting YearMonth after adding the specified number of months.

ToDateInterval()

Returns a DateInterval covering the month represented by this value.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public DateInterval ToDateInterval()

Returns

Type	Description
DateInterval	A DateInterval covering the month represented by this value.

Sample snippet

using NodaTime;
using System;

YearMonth yearMonth = new YearMonth(2019, 5);
DateInterval interval = yearMonth.ToDateInterval();
Console.WriteLine(interval.Start);
Console.WriteLine(interval.End);

Output:

Wednesday, 01 May 2019
Friday, 31 May 2019

ToString()

Returns a string that represents this instance.

Since 3.1.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public override string ToString()

Returns

Type	Description
string	The value of the current instance in the culture-specific default format pattern ("G"), using the current thread's culture to obtain a format provider.

Overrides

ValueType.ToString()

ToString(string?, IFormatProvider?)

Formats the value of the current instance using the specified pattern.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public string ToString(string? patternText, IFormatProvider? formatProvider)

Parameters

Type	Name	Description
string	patternText	The string specifying the pattern to use, or null to use the ISO format pattern ("g").
IFormatProvider	formatProvider	The IFormatProvider to use when formatting the value, or null to use the current thread's culture to obtain a format provider.

Returns

Type	Description
string	A string containing the value of the current instance in the specified format.

Remarks

Unlike most IFormattable implementations, a patternText of null with the current thread's culture does not yield the same result as the parameterless ToString() overload, for backward-compatibility reasons. (It uses the ISO format, which is culture-insensitive.)

Operators

operator ==(YearMonth, YearMonth)

Compares two YearMonth values for equality. See the type documentation for a description of equality semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator ==(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	The first value to compare
YearMonth	rhs	The second value to compare

Returns

Type	Description
bool	True if the two year/month values are the same and in the same calendar; false otherwise

operator >(YearMonth, YearMonth)

Compares two YearMonth values to see if the left one is strictly later than the right one. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator >(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	First operand of the comparison
YearMonth	rhs	Second operand of the comparison

Returns

Type	Description
bool	true if the lhs is strictly later than rhs, false otherwise.

Exceptions

Type	Condition
ArgumentException	The calendar system of rhs is not the same as the calendar of lhs.

operator >=(YearMonth, YearMonth)

Compares two YearMonth values to see if the left one is later than or equal to the right one. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator >=(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	First operand of the comparison
YearMonth	rhs	Second operand of the comparison

Returns

Type	Description
bool	true if the lhs is later than or equal to rhs, false otherwise.

Exceptions

Type	Condition
ArgumentException	The calendar system of rhs is not the same as the calendar of lhs.

operator !=(YearMonth, YearMonth)

Compares two YearMonth values for inequality. See the type documentation for a description of equality semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator !=(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	The first value to compare
YearMonth	rhs	The second value to compare

Returns

Type	Description
bool	False if the two year/month values are the same and in the same calendar; true otherwise

operator <(YearMonth, YearMonth)

Compares two YearMonth values to see if the left one is strictly earlier than the right one. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator <(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	First operand of the comparison
YearMonth	rhs	Second operand of the comparison

Returns

Type	Description
bool	true if the lhs is strictly earlier than rhs, false otherwise.

Exceptions

Type	Condition
ArgumentException	The calendar system of rhs is not the same as the calendar of lhs.

operator <=(YearMonth, YearMonth)

Compares two YearMonth values to see if the left one is earlier than or equal to the right one. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

public static bool operator <=(YearMonth lhs, YearMonth rhs)

Parameters

Type	Name	Description
YearMonth	lhs	First operand of the comparison
YearMonth	rhs	Second operand of the comparison

Returns

Type	Description
bool	true if the lhs is earlier than or equal to rhs, false otherwise.

Exceptions

Type	Condition
ArgumentException	The calendar system of rhs is not the same as the calendar of lhs.

Explicit Interface Implementations

IComparable.CompareTo(object?)

Implementation of CompareTo(object) to compare two YearMonth values. See the type documentation for a description of ordering semantics.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

int IComparable.CompareTo(object? obj)

Parameters

Type	Name	Description
object	obj	The object to compare this value with.

Returns

Type	Description
int	The result of comparing this YearMonth with another one. If obj is null, this method returns a value greater than 0.

Remarks

This uses explicit interface implementation to avoid it being called accidentally. The generic implementation should usually be preferred.

Exceptions

Type	Condition
ArgumentException	obj is non-null but does not refer to an instance of YearMonth, or refers to a value in a different calendar system.

IXmlSerializable.GetSchema()

This method is reserved and should not be used. When implementing the IXmlSerializable interface, you should return null (Nothing in Visual Basic) from this method, and instead, if specifying a custom schema is required, apply the XmlSchemaProviderAttribute to the class.

Since 3.2.x

Availability net6.0, net8.0, netstandard2.0

Declaration

XmlSchema IXmlSerializable.GetSchema()

Returns

Type	Description
XmlSchema	An XmlSchema that describes the XML representation of the object that is produced by the WriteXml(XmlWriter) method and consumed by the ReadXml(XmlReader) method.

IXmlSerializable.ReadXml(XmlReader)

Generates an object from its XML representation.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

void IXmlSerializable.ReadXml(XmlReader reader)

Parameters

Type	Name	Description
XmlReader	reader	The XmlReader stream from which the object is deserialized.

IXmlSerializable.WriteXml(XmlWriter)

Converts an object into its XML representation.

Since 3.0.x

Availability net6.0, net8.0, netstandard2.0

Declaration

void IXmlSerializable.WriteXml(XmlWriter writer)

Parameters

Type	Name	Description
XmlWriter	writer	The XmlWriter stream to which the object is serialized.

Implements

IEquatable<T>

IComparable<T>

IComparable

IFormattable

IXmlSerializable

IComparisonOperators<TSelf, TOther, TResult>

IEqualityOperators<TSelf, TOther, TResult>