XL 2010 Transformer série de chiffre en date

Private Sub Worksheet_Change(ByVal Target As Range)
'---Convertit un nombre de 7 ou 8 chiffres en date---
    Dim d As Variant
    If Not (Intersect(Range("C3:C14"), Target) Is Nothing) And Not Target.Value2 Like "*/*" And Target.Count = 1 Then
        d = CStr(Target.Value2)
         ActiveSheet.Unprotect "123"
        If IsNumeric(d) Then
            Select Case True
            Case Len(CStr(d)) = 5: d = DateValue(Format(d, "0/00/00"))
            Case Len(CStr(d)) = 6: d = DateValue(Format(d, "00/00/00"))
            Case Len(CStr(d)) = 7: d = DateValue(Format(d, "0/00/0000"))
            Case Len(CStr(d)) = 8: d = DateValue(Format(d, "00/00/0000"))
            End Select

            With Target
                If IsDate(d) Then
                    Application.EnableEvents = False
                    .NumberFormat = "dd/mm/yyyy": .Value = d
                Else
                    .NumberFormat = "General": .Value = d
                End If
                ActiveSheet.Protect "123"
            End With
        End If
    End If
    Application.EnableEvents = True
End Sub