CODEWITHSUNDEEP
vb.net
J-J
J-J

Reputation: 1113

How to get starting date in a Week based on week number using vb.net?

I need help on getting the starting date of a week from a given week number in vb.net.

I have combobox binded with items 1-53 as week numbers. What I want to do is whenever I select a specific week number, it will return the first date of that selected week number.

For instance I have selected week Number 46, it must return November 11, 2013 as first date of week number 46.

I have tried the following codes and it returns only the first date of a week from a current week number.

DateAdd("d", -Weekday(Now, FirstDayOfWeek.Monday) + 1, Now)

Is there any possible way that can return my expected output?

Please help me. Thanks in advance.

Upvotes: 2

Views: 17095

Answers (2)

Jike
Jike

Reputation: 31

Public Function FirstDateOfWeek(ByVal Year As Integer, ByVal Week As Integer, Optional FirstDayOfWeek As DayOfWeek = DayOfWeek.Monday) As Date
    Dim dt As Date = New Date(Year, 1, 1)
    If dt.DayOfWeek > 4 Then dt = dt.AddDays(7 - dt.DayOfWeek) Else dt = dt.AddDays(-dt.DayOfWeek)
    dt = dt.AddDays(FirstDayOfWeek)
    Return dt.AddDays(7 * (Week - 1))
End Function

Upvotes: 3

vbigham
vbigham

Reputation: 191

You could try something like this:

Private Sub TestDateAdd()
    Dim weekStart As DateTime = GetWeekStartDate(46, 2013)
    Console.WriteLine(weekStart)
End Sub


Private Function GetWeekStartDate(weekNumber As Integer, year As Integer) As Date
    Dim startDate As New DateTime(year, 1, 1)
    Dim weekDate As DateTime = DateAdd(DateInterval.WeekOfYear, weekNumber - 1, startDate)
    Return DateAdd(DateInterval.Day, (-weekDate.DayOfWeek) + 1, weekDate)
End Function

Disclaimer: I only really tested this with the one input, you probably want to make sure that it works as expected for different years, etc..

Upvotes: 2

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