private void btn_organisateur_Click(object sender, RoutedEventArgs e)
 {
     mdp.mot_passe wind_mdp = new mdp.mot_passe(2);
     wind_mdp.ShowDialog();
 }
 private void btn_benevole_Click(object sender, RoutedEventArgs e)
 {
     mdp.mot_passe wind_mdp = new mdp.mot_passe(1);
     wind_mdp.ShowDialog();
 }