Public Function GetWeek(ByVal targetDate As DateTime) As Integer

        Dim calculationDate As DateTime = New DateTime(targetDate.Year, targetDate.Month, 1)

        Dim calenderCalc As Calendar = CultureInfo.CurrentCulture.Calendar

        Dim da As Integer = calenderCalc.GetWeekOfYear(targetDate, CalendarWeekRule.FirstDay, DayOfWeek.Sunday)

        Dim db As Integer = calenderCalc.GetWeekOfYear(calculationDate, CalendarWeekRule.FirstDay, DayOfWeek.Sunday)

        Dim usWeekNumber As Integer = da - db + 1

        Return usWeekNumber

    End Function

 

 

 

 

    Public Shared Function GetWeekOfYear(ByVal targetDate As DateTime) As Integer

        Return GetWeekOfYear(targetDate, Nothing)

    End Function

 

    Public Shared Function GetWeekOfYear(ByVal targetDate As DateTime, ByVal culture As CultureInfo) As Integer

        If culture Is Nothing Then culture = CultureInfo.CurrentCulture

        Dim weekRule As CalendarWeekRule = culture.DateTimeFormat.CalendarWeekRule

        Dim firstDayOfWeek As DayOfWeek = culture.DateTimeFormat.FirstDayOfWeek

        Return culture.Calendar.GetWeekOfYear(targetDate, weekRule, firstDayOfWeek)

    End Function