How can I construct and return an Excel file through AJAX and an ASP.NET MVC controller?

Question

Attempt:

    // see http://www.aspsnippets.com/Articles/Create-and-download-Excel-file-in-ASPNet.aspx
    [HttpPost]
    protected void FullDump ( object sender , EventArgs e )
    {
        using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["SurveyDbStaging"].ConnectionString))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT * FROM Answers"))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter())
                {
                    cmd.Connection = con;
                    sda.SelectCommand = cmd;
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        using (XLWorkbook wb = new XLWorkbook())
                        {
                            wb.Worksheets.Add(dt, "Answers");

                            Response.Clear();
                            Response.Buffer = true;
                            Response.Charset = "";
                            Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                            Response.AddHeader("content-disposition", "attachment;filename=SqlExport.xlsx");
                            using (MemoryStream MyMemoryStream = new MemoryStream())
                            {
                                wb.SaveAs(MyMemoryStream);
                                MyMemoryStream.WriteTo(Response.OutputStream);
                                Response.Flush();
                                Response.End();
                            }
                        }
                    }
                }
            }
        }
    }

called in the view by

    $('#data-dump-button').click(function(){
        $.ajax({
            url : 'Excel/FullDump',
            method : 'POST',
            success: function () {
                console.log("The success function was called!");
            }
        });
    });

This just gives me

http://thesite.com/Excel/FullDump 404 (NOT FOUND)

in the console. What should I be doing instead?