une petite recherche dans google et voila :
http://www.cpearson.com/excel/DateTimeVBA.htm
 
Monday Of A Given Week Number (WeekStart)
 
This function returns the date of the Monday in a given week number, e.g., the Monday of the 15th week of 1998.  It requires the YearStart function, given above.
 
Public Function WeekStart(WhichWeek As Integer, WhichYear As _
                    Integer) As Date
 
WeekStart = YearStart(WhichYear) + ((WhichWeek - 1) * 7)
 
End Function
 
   
 
First Monday Of The Year (YearStart)
 
The following function was provided by John Green, an Excel MVP from Australia.   It returns the first Monday of the specified year.  This function is used by other functions on this page.
 
Public Function YearStart(WhichYear As Integer) As Date
 
Dim WeekDay As Integer
Dim NewYear As Date
 
NewYear = DateSerial(WhichYear, 1, 1)
WeekDay = (NewYear - 2) Mod 7 'Generate weekday index where Monday = 0
 
If WeekDay < 4 Then
    YearStart = NewYear - WeekDay
Else
    YearStart = NewYear - WeekDay + 7
End If
 
End Function
 
Message édité par friday_13 le 26-08-2005 à 11:26:06