在asp.net mvc中尝试上载文件时,如何解决mum请求长度超出错误

我使用的是mvc,我试图上传一个9MB的文件,但我一直收到一个错误,在mycontroller中显示System.Web.Http.HttpResponseException

<security>
      <requestFiltering>
        <!--<requestLimits maxAllowedContentLength="1073741824" />-->
        <requestLimits maxAllowedContentLength="3000000000" />
      </requestFiltering>
    </security>

<system.web>
    <httpRuntime maxRequestLength="1048576" />
    <httpHandlers>
      <add path="*" verb="*" type="System.Web.HttpNotFoundHandler"/>

    </httpHandlers>

控制器

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;

namespace Marketing_Database.Controllers
{

    #region Multipart form provider class
    public class CustomMultipartFormDataStreamProvider : MultipartFormDataStreamProvider
    {
        public CustomMultipartFormDataStreamProvider(string path)
            : base(path)
        {

        }

        public override string GetLocalFileName(System.Net.Http.Headers.HttpContentHeaders headers)
        {
            string fileName;
            if (!string.IsNullOrWhiteSpace(headers.ContentDisposition.FileName))
            {
                fileName = headers.ContentDisposition.FileName;
            }
            else
            {
                fileName = Guid.NewGuid().ToString() + ".data";
            }
            return fileName.Replace("\"", string.Empty);
        }
    }
    #endregion

    public class FileUploadController : ApiController
    {
        public Task<IEnumerable<string>> Post()
        {
            //throw new Exception("Custom error thrown for script error handling test!");

            if (Request.Content.IsMimeMultipartContent())
            {
                //Simulate large file upload
                System.Threading.Thread.Sleep(5000);


                string fullPath = HttpContext.Current.Server.MapPath("~/Uploads");
                CustomMultipartFormDataStreamProvider streamProvider = new CustomMultipartFormDataStreamProvider(fullPath);
                var task = Request.Content.ReadAsMultipartAsync(streamProvider).ContinueWith(t =>
                {
                    if (t.IsFaulted || t.IsCanceled)
                        throw new HttpResponseException(HttpStatusCode.InternalServerError);

                    var fileInfo = streamProvider.FileData.Select(i =>
                    {
                        var info = new FileInfo(i.LocalFileName);
                        return "File saved as " + info.FullName + " (" + info.Length + ")";
                    });
                    return fileInfo;

                });
                return task;
            }
            else
            {
                throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotAcceptable, "Invalid Request!"));
            }
        }
    }
}