Error running Oracledatareader.Hasrows with cursor without values

Question

I am using Oracledatareader to insert elements of a cursor into a list. The cursor is returned from an oracle db procedure. The problem is that when I have no elements returned on the cursor, the application stops working without error. I want to know how to check if the cursor has elements?

This is the function code that creates the list from the elements returned on the cursor and is in c# Asp.net.

 public List<VagaModel> BuscarVagas(string codCentroCusto, string anoPeriodo, string codPeriodo)
    {

        List<VagaModel> lstVagas = null;

        using (OracleConnection con = new OracleConnection(connectionString))
        {
            using (OracleCommand cmd = con.CreateCommand())
            {
                try
                {
                    cmd.CommandText = "NET_BUSCAR_VAGAS_P1";
                    cmd.CommandType = CommandType.StoredProcedure;

                    cmd.Parameters.Add("vCodCentroCusto", OracleDbType.Int64).Direction = ParameterDirection.Input;
                    cmd.Parameters["vCodCentroCusto"].Value = Convert.ToInt64(codCentroCusto);

                    cmd.Parameters.Add("vAnoPeriodo", OracleDbType.Int32).Direction = ParameterDirection.Input;
                    cmd.Parameters["vAnoPeriodo"].Value = Convert.ToInt32(anoPeriodo);

                    cmd.Parameters.Add("vCodPeriodo", OracleDbType.Int64).Direction = ParameterDirection.Input;
                    cmd.Parameters["vCodPeriodo"].Value = Convert.ToInt64(codPeriodo);


                    cmd.Parameters.Add("vCursor", OracleDbType.RefCursor).Direction = ParameterDirection.Output;

                    con.Open();


                    cmd.ExecuteNonQuery();


                    OracleRefCursor cursor = (OracleRefCursor)cmd.Parameters["vCursor"].Value;



                    using (OracleDataReader dr = cursor.GetDataReader())
                    {
                        if (dr.HasRows)
                        {
                            lstVagas = new List<VagaModel>();

                                while (dr.Read())
                                {
                                    var codVaga = dr.GetValue(0);
                                    var qtdSolteiro = dr.GetValue(1);
                                    var qtdCasal = dr.GetValue(2);
                                    var qtdBeliche = dr.GetValue(3);
                                    var qtdAuxiliar = dr.GetValue(4);
                                    var capVaga = dr.GetValue(5);
                                    var codTbVaga = dr.GetValue(6);

                                    VagaModel vaga = new VagaModel(codVaga.ToString(), qtdSolteiro.ToString(), qtdCasal.ToString(), qtdBeliche.ToString(),
                                        qtdAuxiliar.ToString(), capVaga.ToString(), codTbVaga.ToString());

                                    lstVagas.Add(vaga);
                                }
                        }

                        //dr.Close();
                        //dr.Dispose();

                    } 

                }
                catch (Exception e)
                {

                    throw new Exception(e.Message);
                }
                finally
                {


                    if (con.State == ConnectionState.Open)
                    {
                        con.Close();
                    }
                }
            }
        }

        return lstVagas;
    }