private void modifierToolStripMenuItem_Click(object sender, EventArgs e)
 {
     if (lvart.SelectedIndices.Count == 1)
     {
         String no_cmd = lvart.Items[lvart.SelectedIndices[0]].Text;
         Article art = new Article();
         art.RechercheArticle(no_cmd);
         FajouteArticle modif = new FajouteArticle(art, true);
         DialogResult res = modif.ShowDialog();
         if (res == DialogResult.OK)
         {
             try
             {
                 art.modifierArticle();
                 AfficherListe();
             }
             catch (MonException excep)
             {
                 MessageBox.Show(excep.MessageSysteme(), "Erreur de modification");
             }
         }
     }
 }