create method

public ActionResult Create(Musica musica)
        {
            MembershipUser user = Membership.GetUser();
            string userName = user.UserName;
            if (ModelState.IsValid)
            {
                db.Musicas.Add(new Musica {

                    NomeArtista = userName
                });
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.GeneroId = new SelectList(db.Generos, "GeneroId", "Nome", musica.GeneroId);
            return View(musica);
        }