VB.NET Language in a Nutshell, Second Edition

Name

Year Function

Class

Microsoft.VisualBasic.DateAndTime

Syntax

Year(datevalue)

datevalue (required; Date or valid date expression)

Any valid date expression

Return Value

Integer

Description

Returns an integer representing the year in a given date expression

Rules at a Glance

• If datevalue contains Nothing, Year returns 1. (This assumes that Option Strict is off.) For example:

  Dim oDat As Object
  Console.Writeline(Year(sDat))       ' Displays 1

• If datevalue is a date literal (a date delimited with the # symbol), the year must contain four digits.

Programming Tips and Gotchas

• The validity of the date expression — and the position of the year element within the given date expression — is initially determined by the locale settings of the Windows system. However, some extra intelligence relating to two-digit year values (see the next item in this list) has been built into the Year function, which surpasses the usual comparison of a date expression to the current locale settings.

• What happens when you pass a date over to the Year function containing a two-digit year? Quite simply, when the Year function sees a two-digit year, it assumes that all values equal to or greater than 30 are in the 20th century (i.e., 30 = 1930, 98 = 1998) and that all values less than 30 are in the 21st century (i.e., 29 = 2029, 5 = 2005). Of course, it is much better programming practice to use — and require your clients to use — four-digit years.

See Also

DatePart Function