public ActionResult AddStudentForm(Models.EleveViewModel formData)
        {
            if (formData.Nom != null && formData.Prenom != null && formData.DateNaissance != null && formData.ClassId >= 0)
            {
                // récupération du BusinessManager
                BusinessManager bm = BusinessManager.GetInstance();
                GestionEleves.DAL.Entites.Eleve eleve = new DAL.Entites.Eleve {
                    Nom = formData.Nom, Prenom = formData.Prenom, ClassId = formData.ClassId, DateNaissance = formData.DateNaissance
                };
                int eleveId = bm.AddEleve(eleve);

                string url = $"/Student/Details/{eleveId}";
                return(Redirect(url));
            }

            return(View("AddStudent"));
        }