Afficher numéro semaine de l'année selon la date

Private Sub UserForm_Initialize()
TxtDate = Format(VBA.Date, "dd/mm/yyyy")
TxtMonth = Format(VBA.Date, "mmmm")
TxtWeek = NoSem(VBA.Date)
End Sub

Private Function NoSem(D As Date) As Long
NoSem = VBA.DateSerial(VBA.Year(D + (8 - VBA.Weekday(D)) Mod 7 - 3), 1, 1)
NoSem = ((D - NoSem - 3 + (VBA.Weekday(NoSem) + 1) Mod 7)) \ 7 + 1
End Function