try
    {
        using (StreamWriter sw = File.AppendText(strPath))
        {
            sw.WriteLine("=============PASO 1==========");
            sw.WriteLine("===========fecha============= " + DateTime.Now);
        }
        con = conex.f_getConexion();
        con.Open();
        using (StreamWriter sw = File.AppendText(strPath))
        {
            sw.WriteLine("=============PASO 2==========");
            sw.WriteLine("===========fecha============= " + DateTime.Now);
        }
        cmd = new SqlCommand("pa_man_EmpresaEmisorKey_Lis", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@key", key);

        using (StreamWriter sw = File.AppendText(strPath))
        {
            sw.WriteLine("=============PASO 3==========");
            sw.WriteLine("===========fecha============= " + DateTime.Now);
        }
        SqlDataReader registros = cmd.ExecuteReader();
        Contribuyente obj = new Contribuyente();

        if (registros.Read())
        {
            using (StreamWriter sw = File.AppendText(strPath))
            {
                sw.WriteLine("=============PASO 4==========");
                sw.WriteLine("===========fecha============= " + DateTime.Now);
            }
            obj.IdContribuyente = Int32.Parse(registros["IdContribuyente"].ToString());
            using (StreamWriter sw = File.AppendText(strPath))
            {
                sw.WriteLine("=============PASO 5==========");
                sw.WriteLine("===========fecha============= " + DateTime.Now);
            }
        }
        using (StreamWriter sw = File.AppendText(strPath))
        {
            sw.WriteLine("=============PASO 6==========");
            sw.WriteLine("===========fecha============= " + DateTime.Now);
        }
        registros.Close();
        con.Close();
        return obj;
    }
    catch (Exception ex)
    {
        using (StreamWriter sw = File.AppendText(strPath))
        {
            sw.WriteLine("=============PASO 7==========");
            sw.WriteLine("===========fecha============= " + DateTime.Now);
        }
        throw;
    }