Private Sub TextBox1.Text_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
If e.KeyChar < "0" Or e.KeyChar > "9" And e.KeyChar <> " 8" Then
MsgBox("Veuillez saisir des chiffres !", MsgBoxStyle.Exclamation, "Erreur")
e.KeyChar = ""
End If
End Sub