Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
'2eme requete
If Target.Column = 2 Or Target.Column = 4 Then
If Application.CountIf(Sheets("saisie_base").Range("C C21:CC" & [CC21].End(xlDown).Row), Cells(Target.Row, 2) & Cells(Target.Row, 4)) > 1 Then
MsgBox "Attention : le numéro de 'sous plan' saisi est déjà existant pour ce budget!"
End If
End If
'1ere requete
If Target.Column >= 2 And Target.Column <= 31 Then
If Cells(Target.Row, 27).Value = Date Then Exit Sub
Cells(Target.Row, 27).Value = Date
End If
End Sub