Getting Dates of Current week does not work as expected - vb.net

Question

iam trying to get the Dates (Monday - Sunday) for the current Week.
This is my current Code:
Dim kw As Integer = DatePart(DateInterval.WeekOfYear, Now, , FirstWeekOfYear.FirstFourDays)
If DatePart(DateInterval.Weekday, Now, Microsoft.VisualBasic.FirstDayOfWeek.Sunday) = 6 Then
kw = kw + 1
End If
Dim CurrDateFirstDay As Date = DateAdd(DateInterval.Day, 1, ReturnDateForWeekNumber(kw))
For i = 1 To 7
strCurrDay = FormatDateTime(CurrDateFirstDay, DateFormat.LongDate)
........
My Problem is that my code starts at 16.01.2013 and the last date is Thuesday 22.01.2013 next week. Why is that? Why does he start Wednesday 16.01.2013 and not Monday 14.01.2013? And why do i get returned dates of the next week? What iam doing wrong?
Edit:
ReturnDateForWeekNumber:
Public Shared Function ReturnDateForWeekNumber(ByVal iWeek As Integer) As DateTime
Return DateAdd(DateInterval.WeekOfYear, iWeek - 1, FirstDayOfYear)
End Function

Answer 1

What am I doing wrong?
You should step through your code in the debugger and observe the result, as I did:
Dim kw As Integer = DatePart(DateInterval.WeekOfYear, Now, , FirstWeekOfYear.FirstFourDays)
This returns the current week, which is week 3.
If DatePart(DateInterval.Weekday, Now, Microsoft.VisualBasic.FirstDayOfWeek.Sunday) = 6 Then
kw = kw + 1
End If
This checks if the weekday is the 6th day of the week (friday). We're not friday so If condition is not entered.
Dim CurrDateFirstDay As Date = DateAdd(DateInterval.Day, 1, ReturnDateForWeekNumber(kw))
This adds one day to the result of ReturnDateForWeekNumber, which returns:
Return DateAdd(DateInterval.WeekOfYear, iWeek - 1, FirstDayOfYear)
This adds 2 (week 3 minus 1) weeks to the first day of the year (Jan 1st), a tuesday. Jan 1st + 2 weeks = January 15th.
Now remember that you add one day to ReturnDateForWeekNumber, that's why CurrDateFirstDay has a value of January 16th.
Edit
I think your code is overly complicated and uses a lot of legacy VB6 functions. I would do it this way:
Dim myDate As Date = DateTime.Today
Dim dayDiff As Integer = myDate.DayOfWeek - DayOfWeek.Monday
Dim currentDay As Date = myDate.AddDays(-dayDiff) 'Monday
For i = 1 to 7
Console.WriteLine(currentDay)
'Do something with current day
currentDay = currentDay.AddDays(1)
Next
You might have to do some adjustments for your case but I believe this approach is simpler and less error prone.

Answer 2

Dim dateStartDateOfWeek As Date = GetWeekStartDate(52, 2014)
Dim dateEndDateOfWeek As Date = DateAdd(DateInterval.Day, 7, dateStartDateOfWeek)
Private Function GetWeekStartDate(ByVal weekNumber As Integer, ByVal 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