title: There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'Carrera'
body: <p>I'm having trouble when handling the Post request for my controller:</p>
  
  <pre><code>[HttpGet]
  public ActionResult Crear()
  {
      CarreraRepository carreraRepository = new CarreraRepository();
      var carreras = carreraRepository.FindAll().OrderBy(x =&gt; x.Nombre);
      var carrerasList = new SelectList(carreras, "ID", "Nombre");
      ViewData["Carreras"] = carrerasList;
  
      Materia materia = new Materia();
      return View(materia);        
  }
  
  [HttpPost]
  public ActionResult Crear(Materia materia, FormCollection values)
  {
      if (ModelState.IsValid)
      {
          repo.Add(materia);
          repo.Save();
  
          return RedirectToAction("Index");
      }
      return View(materia);
  }
  </code></pre>
  
  <p>When the HttpGet action runs, the form to create renders fine. The values are set correctly on the DropDownList and everything is peachy; when I try to submit the form (run the HttpPost action) I receive the error.</p>
  
  <p>Can anyone help me out?</p>
  
  <p>Is it because the HttpPost doesn't have a ViewData declared? Thanks for the help.</p>