vb.net find 4th Wednesday of month with visual basic - vb.net

Question

I am trying to find the fourth Wednesday of the current Month and Year when a form loads
I have converted numerous C# code to Visual Basic with no results
Would someone explain what is wrong with this code OR explain how to accomplish this in VB Code
Private Sub SurroundingSub()
Dim thisDate As Date = Today
tbMonth.Text = thisDate.ToString("MMMM")
tbYear.Text = thisDate.ToString("yyyy")
Dim month As Integer
month = tbMonth.Text
Dim year As Integer
year = tbYear.Text
Dim fourthWed As Date = New Date(year, month, 4)
tbFour.Text = fourthWed.ToLongDateString
While fourthWed.DayOfWeek <> DayOfWeek.Wednesday
fourthWed = fourthWed.AddDays(1)
tbFour.Text = fourthWed.ToShortDateString
End While
End Sub
This is a JavaFX statement that I am trying to implement in VB.Net
if(TorF.equals("F") && today.isAfter(fourthTUEofMONTH))
This sets the date
public void setDATES() throws IOException, SQLException{
today = LocalDate.now();
fourthTUEofMONTH = LocalDate.now();
fourthTUEofMONTH = fourthTUEofMONTH.with(TemporalAdjusters.dayOfWeekInMonth(4, DayOfWeek.TUESDAY));
endMONTH = LocalDate.now();
endMONTH = endMONTH.with(TemporalAdjusters.lastDayOfMonth());
}

Answer 1

For a more general solution, with my function you can easily find the first, second, third, forth or fifth sunday, monday, tuesday, wednesday or whatever you want:
Public Function GetXDayOfWeek(Day As DateTime,
DayOfWeek As DayOfWeek,
Optional Index As Integer = 1) As DateTime
Dim First As New Date(Day.Year, Day.Month, 1)
Dim Diff As Integer = (DayOfWeek - First.DayOfWeek + 7) Mod 7
Return First.AddDays(Diff + (Index - 1) * 7)
End Function
So if you want to find the forth wednesday of the current month, use it like:
Dim DateToFind As DateTime = GetXDayOfWeek(Today, DayOfWeek.Wednesday, 4)

Answer 2

Your while statement will stop on the first Wednesday it finds, not the fourth. Keep track of the number of Wednesdays you encounter as you iterate and once you find the fourth then you can update tbFour.
Also as mentioned in the comments you'll want to start at the first day of the year.
Dim fourthWed As Date = New Date(year, month, 1)
Dim wednesdayCursor As Integer = 0
While wednesdayCursor < 4
If fourthWed.DayOfWeek = DayOfWeek.Wednesday Then
wednesdayCursor += 1
End If
fourthWed = fourthWed.AddDays(1)
End While
'Subtract one day because we added one on loop:
fbFour.Text = fourthWed.AddDays(-1).ToShortDateString()

Answer 3

You should make the function of getting the fourth Wednesday into a separate method, perhaps generalizing it for any day of the week, but just for the fourth Wednesday...
Module Module1
Function FourthWedOfMonth(dt As DateTime) As Integer
Dim currDate = New DateTime(dt.Year, dt.Month, 1)
Dim nWednesdays = 0
While nWednesdays < 4
If currDate.DayOfWeek = DayOfWeek.Wednesday Then
nWednesdays += 1
End If
currDate = currDate.AddDays(1)
End While
Return currDate.Day - 1
End Function
Sub Main()
For mo = 1 To 12
Console.Write(FourthWedOfMonth(New DateTime(2020, mo, 17)) & " ")
Next
Console.ReadLine()
End Sub
End Module
Outputs the correct days for 2020:
22 26 25 22 27 24 22 26 23 28 25 23
If you wanted the DateTime of the fourth Wednesday, you could
Function FourthWedOfMonth(dt As DateTime) As DateTime
Dim currDate = New DateTime(dt.Year, dt.Month, 1)
Dim nWednesdays = 0
While nWednesdays < 4
If currDate.DayOfWeek = DayOfWeek.Wednesday Then
nWednesdays += 1
End If
currDate = currDate.AddDays(1)
End While
Return New DateTime(dt.Year, dt.Month, currDate.Day - 1)
End Function
and then Console.WriteLine(FourthWedOfMonth(DateTime.Today).ToString("dd-MMM-yyyy")) would output "22-Jul-2020" (at the time of writing).

Answer 4

I'd find the fourth Wednesday of the current month this way:
Private Sub FourthWednesdayOfCurrentMonth()
Dim firstOfMonth As DateTime = DateTime.Today.AddDays(-1 * (DateTime.Today.Day - 1))
Dim firstWednesday As DateTime = firstOfMonth.AddDays((7 + (DayOfWeek.Wednesday - firstOfMonth.DayOfWeek)) Mod 7)
Dim fourthWednesday As DateTime = firstWednesday.AddDays(21)
tbYear.Text = fourthWednesday.Year
tbMonth.Text = fourthWednesday.Month
tbFour.Text = fourthWednesday.Day
End Sub
Written generically for any day of the week, that would change to:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim fourthWednesday As DateTime = FourthWeekDayOfCurrentMonth(DayOfWeek.Wednesday)
tbYear.Text = fourthWednesday.Year
tbMonth.Text = fourthWednesday.Month
tbFour.Text = fourthWednesday.Day
End Sub
Private Function FourthWeekDayOfCurrentMonth(ByVal WeekDay As DayOfWeek) As DateTime
Dim firstOfMonth As DateTime = DateTime.Today.AddDays(-1 * (DateTime.Today.Day - 1))
Dim firstWeekday As DateTime = firstOfMonth.AddDays((7 + (WeekDay - firstOfMonth.DayOfWeek)) Mod 7)
Return firstWeekday.AddDays(21)
End Function