dynamic datasource asp.net mvc

I am trying to build a datatable based off a user defined function. I see a post where code is given on how to grab the column names dynamically: https://datatables.net/forums/discussion/comment/142403#Comment_142403

However, I am having trouble getting the data into the correct format. If you look at my commented out lines, there are several techniques I have tried (and you can probably tell by what I tried that I am very new to this )

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Net.Http.Formatting;
using System.Web;
using System.Web.Http;
using DataTables;
using Billing.Models;
using Newtonsoft.Json;

namespace Billing.Controllers
{
    public class ToGenerateController : ApiController
    {
        [Route("api/ToGenerate")]
        [HttpGet]
        [HttpPost]
        public IHttpActionResult toGenerate()
        {
            var request = HttpContext.Current.Request;
            var settings = Properties.Settings.Default;
            var AsOfCookie = request.Cookies["AsOfDate"].Value;
            string query = "select * from udf_FundOrgFTE_AdjustedFTEPercentages ('" + AsOfCookie + "')";
            string connectionString = settings.DbConnection;

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                SqlCommand command = new SqlCommand(query, conn);

                conn.Open();
                SqlDataReader reader = command.ExecuteReader();
                var dt = new System.Data.DataTable();
                dt.Load(reader);
                object[] result = new object[dt.Rows.Count + 1];

                for (int i = 0; i <= dt.Rows.Count - 1; i++)
                {
                    result[i] = dt.Rows[i].ItemArray;
                }

                reader.Close();
                return Json( result);
                //string strArray = "{ 'draw':null,'data':[" + result.ToString() + "]}" ;
                //return Json( strArray );
                //var json = JsonConvert.SerializeObject(result);
                
                //return Json(json);
                //return Json("{ 'draw':null,'data':[" + result + "]}");
            }
        }

    }
}