InvoiceTrackDataController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using TeamDBAwesome.SqlService;
using TeamDBAwesome.Models;
using Newtonsoft.Json;

namespace TeamDBAwesome.Controllers
{
    public class InvoiceTrackDataController : ApiController
    {
        public HttpResponseMessage Get(int invoiceId)
        {
            MySqlService dbService = new MySqlService();

            List<Track> trackList = dbService.getInvoiceTracks(invoiceId);
            
            string serialzed = JsonConvert.SerializeObject(trackList);

            HttpResponseMessage message = new HttpResponseMessage(HttpStatusCode.OK);
            message.Content = new StringContent(serialzed);

            return message;

        }
    }
}