I cannot capture the post by webapi c#

Question

good morning. I’ve been trying for a few days trying to capture a POST made in Javascript by webapi c# and the most I can is the webapi telling me that the expected parameter is NULL.

var objFornecedor = {
                ID_FORNECEDOR: 38,
                NOME: "cleverton teste",
                CNPJ: "546546546546",
                ENDERECO: "rua c",
                BAIRRO: "novo teste",
                CIDADE: "serrinha",
                SITUACAO: "1",
                DATA_CADASTRO: new Date(2015,02,02)
    }


    $.ajax({
                  contentType: 'application/json; charset=utf-8',
    data: objFornecedor,
          url: 'http://localhost:3190/servicowebapi/fornecedor/incluir',
      success: function(retorno)
        {
              alert('funcionou');..........

and here are the codes you receive

  [HttpPost]
  [ActionName("incluir")]
  public void Post(FORNECEDOR objFornecedor)
  {
      ctx.FORNECEDOR.Add(objFornecedor);
      ctx.SaveChanges();
  }

Call me that mistake. An Exception of type 'System.Argumentnullexception' occurred in Entityframework.dll but was not handled in user code

Additional information: Value cannot be null. ctx.FORNECEDOR.Add(objFornecedor); objFornecedor is NULL

and here follows my class SUPPLIER

public partial class FORNECEDOR
{
    public int ID_FORNECEDOR { get; set; }
    public string NOME { get; set; }
    public string CNPJ { get; set; }
    public string ENDERECO { get; set; }
    public string BAIRRO { get; set; }
    public string CIDADE { get; set; }
    public string SITUACAO { get; set; }
    public Nullable<System.DateTime> DATA_CADASTRO { get; set; }
}

Answer 1

Use the JSON.stringify:

$.ajax({
    type:'POST',
    contentType: 'application/json; charset=utf-8',
    data: JSON.stringify(objFornecedor),
...

Answer 2

Try it this way:

var objFornecedor = {
        ID_FORNECEDOR: 38,
        NOME: "cleverton teste",
        CNPJ: "546546546546",
        ENDERECO: "rua c",
        BAIRRO: "novo teste",
        CIDADE: "serrinha",
        SITUACAO: "1",
        DATA_CADASTRO: new Date(2015, 02, 02)
    };

    $.ajax({
        dataType: "json",
        contentType: "application/json;charset=utf-8",
        data: JSON.stringify(objFornecedor),
        type: 'POST',
        url: 'http://localhost:3190/servicowebapi/fornecedor/incluir',
        success: function (retorno) {
            alert('funcionou');
        }
    });