VB.NET Language in a Nutshell, Second Edition

Name

Month Function

Class

Microsoft.VisualBasic.DateAndTime

Syntax

Month(datevalue)

datevalue (required; date)

Date variable or literal date

Return Value

An Integer between 1 and 12

Description

Returns an integer representing the month of the year of a given date expression

Rules at a Glance

If datevalue contains Nothing, Month returns Nothing.

Programming Tips and Gotchas

• The validity of the date expression, as well as the position of the month element within the date expression, is initially determined by the locale settings of the current Windows system. However, some intelligence has been built into the Month function that surpasses the usual comparison of a date expression to the current locale settings. For example, on a Windows machine set to US date format (mm/dd/yyyy), the date “13/12/1998” would technically be illegal. However, the Month function returns 12 when passed this date. The basic rule for the Month function is that if the system-defined month element is outside legal bounds (i.e., greater than 12), the system-defined day element is assumed to be the month and is returned by the function.

• Since the IsDate function adheres to the same rules and assumptions as Month, it can be used to determine whether a date is valid before passing it to the Month function.

• Visual Basic also has a new MonthName function for returning the name of the month.

• You can also use the DatePart function.

See Also

Day Function, Year Function