Opposite weekOfyear

[tomi24]

Hi,

with this code I get the week number of the year:

Imports System.Globalization

Public Class Form1
    Dim dateNow = DateTime.Now
    Dim dfi = DateTimeFormatInfo.CurrentInfo
    Dim calendar = dfi.Calendar

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        ' using Thursday because I can.
        Dim weekOfyear = calendar.GetWeekOfYear(dateNow, dfi.CalendarWeekRule, DayOfWeek.Thursday)

        Label1.Text = weekOfyear
    End Sub
End Class

Should I do the opposite, that is, from the weekOfyear derive the date (dd/mm/yyyy)…? thanks..

[jmcilhinney]

Should I do the opposite

Do you actually mean "how can I do the opposite"? Assuming you do, how do you think you should do it? The logic should pretty simple so how about you put some thought into first and then ask us to help if it does work. You don't actually need any programming experience to come up with the logic, so anyone can do that. You just need to work out what the dates for the first week are, based on the day of the week the year starts on, and then add the appropriate multiple of 7 days. Make some effort on your own behalf first, then we can help you fix it if it doesn't work. You don't even know that you can't do it if you don't even try. Trying and failing is part of learning so, if you want to learn, don't avoid it.

[tomi24]

Apart from the various formulas and logics etc… and this was quite simple…

I meant if there was a function already made like calendar.GetWeekOfYear that by giving the number of weeks and the year returned the date…

I was looking for something like this:

Label1.Text = DateAdd("ww", NSett - 1, DateSerial(Year(Now), 1, 1))

anyway thanks for the interest…

[dbasnett]

Apart from the various formulas and logics etc… and this was quite simple…

I meant if there was a function already made like calendar.GetWeekOfYear that by giving the number of weeks and the year returned the date…

I was looking for something like this:

Label1.Text = DateAdd("ww", NSett - 1, DateSerial(Year(Now), 1, 1))

anyway thanks for the interest…

I feel like I'm missing it, but is this what you want,

    Public Function DateFromWeekNum(year As Integer, WeekNumber As Integer) As Date
        Dim rv As New Date(year, 1, 1)
        rv = rv.AddDays(WeekNumber * 7)
        Return rv
    End Function

[techgnome]

What date should it return tho? At best it can only return the date of the beginning of the week... you can give GetWeekOfYear a date and it returns which week that date is on ... but given a week, you can't restore the original date. Also typical functions in libraries tend to be used a lot. My guess is that since people already have the date going from date to week of year is much more commonly done, than going the other way around.


-tg