Agnes,
You can use DateTime.AddDays(7) to add a week or AddDays(-7) to subtract a
week from a specific date.
Dim today As DateTime = #10/21/2004#
lastWeek = today.AddDays(7)
If you want to adjust a date to a specific day of week you can use something
like:
Private Shared Function FirstDayOfWeek(ByVal day As DateTime, ByVal
weekStarts As DayOfWeek) As DateTime
Return day.AddDays(weekStarts - day.DayOfWeek)
End Function
Public Shared Sub Main()
Dim today As DateTime = #10/21/2004#
Dim lastWeek As DateTime = today.AddDays(-7)
Dim nextWeek As DateTime = today.AddDays(7)
Dim lastMonday As DateTime = FirstDayOfWeek(lastWeek,
DayOfWeek.Monday)
Dim nextMonday As DateTime = FirstDayOfWeek(nextWeek,
DayOfWeek.Monday)
Debug.WriteLine(today, "today")
Debug.WriteLine(lastWeek, "last week")
Debug.WriteLine(lastMonday, "last monday")
Debug.WriteLine(nextWeek, "next week")
Debug.WriteLine(nextMonday, "next monday")
End Sub
If you want to find a date in a specific week of the year you can use:
Public Function GetDateFromWeek(ByVal year As Integer, _
ByVal week As Integer, _
ByVal dayOfweek As DayOfWeek) Ad Date
Dim firstOfYear As New Date(year, 1, 1)
Return firstOfYear.AddDays((week - 1) * 7 + dayOfWeek _
- firstOfYear.DayOfWeek)
End Function
Then you can call it as:
Dim week As Date
week = GetDateFromWeek(2004, 42, DayOfWeek.Monday)
I will leave calculating the Week Of Year function for you.
Remember that Date is simply an alias for DateTime.
Hope this helps
Jay
