Error 500 in ajax request with Asp.net mvc

Question

Good morning,

I got a problem I can’t fix. I made a simple ajax request in my code to fill the fields automatically if Cpf is already registered in the database.

Well, the day I did everything worked out and it was working great, but now out of the blue, he’s giving Error 500 and says q can’t find my Action and he enters the action, goes to the bank, gets the result, but when he returns he won’t go to View.

Can someone please help me?!

public class ParticipanteController : Controller
{
    mconfEntities db = new mconfEntities();
    // GET: Participante
    public ActionResult Index()
    {
        return View();
    }

    [HttpPost]
    public JsonResult BuscaDados(string cpf)
    {
        string pesquisaCpf = cpf.Replace(".", "");

        var dados = db.Participante.FirstOrDefault(p => p.cpf == pesquisaCpf);

        return Json(dados);
    }

    public ActionResult Create()
    {
        var evento = db.Evento;

        ViewBag.conferencia = new SelectList(evento, "eventoUID", "descricao");

        return View();
    }

    [HttpPost]
    public ActionResult Create(Participante model)
    {
        if (ModelState.IsValid)
        {
            try
            {
                Participante p = new Participante()
                {
                    cpf = model.cpf,
                    nome = model.nome,
                    email = model.email,
                    telefone = model.telefone,
                    municipio = model.municipio,
                    unidadeSaude = model.unidadeSaude,
                    equipeSaude = model.equipeSaude,
                    categoriaProfissional = model.categoriaProfissional
                };

                db.Participante.Add(p);
                db.SaveChanges();

                return Redirect("http://www.google.com");
            }
            catch (EntityException ex)
            {
                TempData["erro"] = "Erro ao cadastrar participante - " + ex.Message;
                return View();
            }
        }
        else
        {
            TempData["erro"] = "Participante Inválido";
            return RedirectToAction("Create");
        }
    }
}


<script>
$(document).ready(

Function () { $('#Cpf'). focusout(Function() { Debugger; var cpfData = $('#Cpf'). val(). replace('.','). replace('-','');

      $.ajax
      ({
          url: '/Participante/BuscaDados/',
          type: "POST",
          data: { cpf: cpfData },
          success: function (data) {
              $('#nome').val(data.nome);
              $('#email').val(data.email);
              $('#telefone').val(data.telefone);
              $('#municipio').val(data.município);
              $('#unidadeSaude').val(data.unidadeSaude);
              $('#equipeSaude').val(data.equipeSaude);
              $('#categoriaProfissional').val(data.categoriaProfissional);
          }
      });
  });

});

The mistake:

Answer 1

I went through something like this the other day,

Use the Fiddler program to verify which requests and which replies you are sending.

Regarding the error may be linked to the return type, try the return as follows:

return Json(dados, JsonRequestBehavior.AllowGet);

or

//retorna uma string json
return JavaScriptSerializer.Serialize(dados);

Now use Fiddler to verify that the response is being sent containing JSON

Answer 2

I was able to solve, after a few days without sleep and using the Fiddler that Fernando Medeiros indicated, I discovered that it was a Circular reference problem in the classes created by the Entity framework.

I solved by putting a .Select(t => new {t.nome, t.email, ...}) before . Where() and in this way he was able to identify which table I was trying to get the data.

The strangest thing about my case is that the day I made the Code the stop worked and suddenly stopped working...

Thank you very much to everyone who helped...

Solution:

[HttpGet]
    public JsonResult BuscaDados(string cpf)
    {      
        var dados = db.Participante.Select(t => new {t.cpf, t.nome, t.email, t.telefone, t.municipio, t.unidadeSaude, t.equipeSaude, t.categoriaProfissional } ).Where(p => p.cpf == cpf);

        return Json(dados, JsonRequestBehavior.AllowGet);
    }