DateTime.AddMonths Method

July 28, 2014

Returns a new DateTime that adds the specified number of months to the value of this instance.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public DateTime AddMonths(
	int months
)

Parameters

months
Type: System.Int32
The number of months to add. This value can be positive or negative.

Return Value

Type: System.DateTime
An object whose value is the sum of the date and time represented by this instance and months.

ExceptionCondition
ArgumentOutOfRangeException

The resulting DateTime is earlier than DateTime.MinValue or later than DateTime.MaxValue.

-or-

months is less than -120,000 or greater than 120,000.

This method does not change the value of this DateTime object. Instead, a new DateTime object is returned whose value is the result of this operation.

The AddMonths method calculates the resulting month and year, taking into account leap years and the number of days in a month, then adjusts the day part of the resulting DateTime object. If the resulting day is not a valid day in the resulting month, the last valid day of the resulting month is used. For example, March 31st + 1 month = April 30th. The time-of-day part of the resulting DateTime object remains the same as this instance.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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