vb.net - How do I get first, second or last Tuesday (or any day of the week) of a given month

Question

I was looking for a function in VB.net that returns the date of the specified weekday of a given week in a month. Something similar to Outlook appointments.

for example: First Monday of the month, Second Thursday of the month or Last Saturday of the month

I searched but couldn't find anything versatile enough to all the options. So I created my own and would like to share it.

Answer 1

Here is what I came up with:

Public Function GetDate()

    Dim dt As Date = Today

    Dim FirstWeek As Integer = 1
    Dim SecondWeek As Integer = 2
    Dim ThirdWeek As Integer = 3
    Dim FourthWeek As Integer = 4
    Dim LastWeek As Integer = 5

    MsgBox(GetNthDayOfNthWeek(dt, DayOfWeek.Monday, LastWeek).ToString)

End Function

Public Function GetNthDayOfNthWeek(ByVal dt As Date, ByVal DayofWeek As Integer, ByVal WhichWeek As Integer) As Date
    'specify which day of which week of a month and this function will get the date
    'this function uses the month and year of the date provided

    'get first day of the given date
    Dim dtFirst As Date = DateSerial(dt.Year, dt.Month, 1)

    'get first DayOfWeek of the month
    Dim dtRet As Date = dtFirst.AddDays(6 - dtFirst.AddDays(-(DayofWeek + 1)).DayOfWeek)

    'get which week
    dtRet = dtRet.AddDays((WhichWeek - 1) * 7)

    'if day is past end of month then adjust backwards a week
    If dtRet >= dtFirst.AddMonths(1) Then
        dtRet = dtRet.AddDays(-7)
    End If

    'return
    Return dtRet

End Function

Enjoy!