Public Function IsValidDate(ByVal Year As UShort, ByVal Month As Byte, ByVal Day As Byte) As Boolean ' Determine whether the given date exists in the current Gregorian calendar ' Example: IsValidDate(2006, 11, 30) = True, IsValidDate(2006, 11, 31) = False ' ' Visustin sample algorithm ' ©2006 Aivosto Oy (www.aivosto.com) If Month >= 1 And Month <= 12 Then If Day >= 1 Then ' Compare to maximum days in this month If Day <= DaysInMonth(Year, Month) Then Return True ' Valid date Else Return False ' Day exceeds max days in month End If Else Return False ' Day cannot be below 1 End If Else Return False ' Invalid month End If End Function
Hide code	Visustin flow chart for VB.NET