Hej på er. Jag är inte den som vet så mycket om vb.net men undrar om det finns något enkelt sätt att få ta i aktuellt veckonummer.

Hittade den här funktionen när jag googlade:

http://konsulent.sandelien.no/VB_help/Week/ISO8601_VB.htm

    ' Author: Simen Sandelien
    ' Purpose: Calculate ISO 8601 week number for a date
    ' Created: 2005-05-11
    ' Input Parameters: The date for which ISO weeknumber should be calculated
    ' Returns: ISO Week number
    ' Using Monday as the first day of the week.
    ' This is VB.NET port of the C# code
    ' published at http://konsulent.sandelien.no/VB_help/Week/
    Private Function Weeknumber_Entire4DayWeekRule(ByVal inDate As DateTime) As Integer
        Const JAN As Integer = 1
        Const DEC As Integer = 12
        Const LASTDAYOFDEC As Integer = 31
        Const FIRSTDAYOFJAN As Integer = 1
        Const THURSDAY As Integer = 4
        Dim ThursdayFlag As Boolean = False

        ' Get the day number since the beginning of the year
        Dim DayOfYear As Integer = inDate.DayOfYear

        ' Get the numeric weekday of the first day of the
        ' year (using sunday as FirstDay)
        Dim StartWeekDayOfYear As Integer = _
           DirectCast(New DateTime(inDate.Year, JAN, FIRSTDAYOFJAN).DayOfWeek, Integer)
        Dim EndWeekDayOfYear As Integer = _
            DirectCast(New DateTime(inDate.Year, DEC, LASTDAYOFDEC).DayOfWeek, Integer)

        ' Compensate for the fact that we are using monday
        ' as the first day of the week
        If StartWeekDayOfYear = 0 Then
            StartWeekDayOfYear = 7
        End If
        If EndWeekDayOfYear = 0 Then
            EndWeekDayOfYear = 7
        End If

        ' Calculate the number of days in the first and last week
        Dim DaysInFirstWeek As Integer = 8 - StartWeekDayOfYear
        Dim DaysInLastWeek As Integer = 8 - EndWeekDayOfYear

       ' If the year either starts or ends on a thursday it will have a 53rd week
        If StartWeekDayOfYear = THURSDAY OrElse EndWeekDayOfYear = THURSDAY Then
            ThursdayFlag = True
       End If

        ' We begin by calculating the number of FULL weeks between the start of the year and
        ' our date. The number is rounded up, so the smallest possible value is 0.
        Dim FullWeeks As Integer = _
            CType(Math.Ceiling((DayOfYear - DaysInFirstWeek) / 7), Integer)
 
        Dim WeekNumber As Integer = FullWeeks

        ' If the first week of the year has at least four days, then the actual week number for our date
        ' can be incremented by one.
       If DaysInFirstWeek >= THURSDAY Then
            WeekNumber = WeekNumber + 1
        End If

       ' If week number is larger than week 52 (and the year doesn't either start or end on a thursday)
        ' then the correct week number is 1.
       If WeekNumber > 52 AndAlso Not ThursdayFlag Then
            WeekNumber = 1
        End If

        'If week number is still 0, it means that we are trying to evaluate the week number for a
        'week that belongs in the previous year (since that week has 3 days or less in our date's year).
        'We therefore make a recursive call using the last day of the previous year.
        If WeekNumber = 0 Then
            WeekNumber = Weeknumber_Entire4DayWeekRule( _ 
                New DateTime(inDate.Year - 1, DEC, LASTDAYOFDEC))
        End If
        Return WeekNumber
    End Function 

Det finns också möjlighet att få ut veckonummer med den inbyggda DatePart-funktionen:
Dim Year As Integer= Microsoft.VisualBasic.DatePart(DateInterval.Year, DateTime.Today, Microsoft.VisualBasic.FirstDayOfWeek.Monday, FirstWeekOfYear.FirstFourDays)

Jag vet att om jag säger att det finns en inbyggd så får jag på snoken inom 2 minuter då den vid ett fåtal tillfällen ger fel vecka. Men jag gör det ändå...Microsofts lösning finns här:

int week = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
               DateTime.Now, 
               System.Globalization.CalendarWeekRule.FirstFourDayWeek, 
               DayOfWeek.Monday);

jag tackar för de svar jag fått och ska testa dem...

Chris, när ger den fel vecka?