Private Sub TextBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
If KeyCode = 13 And TextBox1.Value <> "" Then
If Not IsError(Evaluate(TextBox1.Value)) Then TextBox1 = Evaluate(TextBox1.Value) Else MsgBox "la formule comporte une(des)erreur(s)"
End If
End Sub