Private Sub ComboBox_nom_Change()
Dim Recherche As Range
Dim MaVariable As String
MaVariable = Me.ComboBox_nom
If MaVariable <> "" Then
With ThisWorkbook.Sheets("Clients")
Set Recherche = .Range("B:B").Find(What:=MaVariable, LookIn:=xlValues, LookAt:=xlWhole)
If Not Recherche Is Nothing Then
etc.
Else
Me.Hide
Ajouter_client.Nom = Application.Proper(MaVariable)
Ajouter_client.Show 0
UserForm_Initialize
Me.Show
End If
End With
End If
End Sub