HttpPostedFileBase始终保持为空mvc 5

Question

我知道这个问题很多次，但没有回答它对我有用。 我的观点就像......

<div class="form-group">
            @Html.LabelFor(model => model.VHF, new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.VHF)
                @Html.ValidationMessageFor(model => model.VHF)
            </div>
        </div>

        @using (Html.BeginForm("Create", "Radio", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            <input type="file" name="uploadFile" />
        }

        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Create" class="btn btn-default" />
            </div>
        </div>

我的控制器......

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Create([Bind(Include = "Model_No,Manufacturer_Id,Display,Channel_Capacity,Max_Freq_Separation,UHF_R1,UHF_R2,VHF,Pic")] sys_Radio_Models radioModels, HttpPostedFileBase uploadFile)
    {
        if (ModelState.IsValid)
        {
            if(uploadFile != null && uploadFile.ContentLength > 0)
            {
                //File size must be 2 MB as maximum
                if (uploadFile.ContentLength > (2 * 1024 * 1024))
                {
                    ModelState.AddModelError("CustomError", "File size must be less than 2 MB");
                    return View();
                }
                //File types allowed : jpeg, jpg, png, gif and tif
                if (!(uploadFile.ContentType == "image/jpeg"
                    || uploadFile.ContentType == "image/jpg"
                    || uploadFile.ContentType == "image/png"
                    || uploadFile.ContentType == "image/gif"
                    || uploadFile.ContentType == "image/tif"))
                {
                    ModelState.AddModelError("CustomError", "File types allowed : jpeg, jpg, png, gif and tif");
                    return View();
                }

                byte[] data = new byte[uploadFile.ContentLength];
                uploadFile.InputStream.Read(data, 0, uploadFile.ContentLength);

                radioModels.Pic = data;
            }
            else
            {
                // Set the default image:
                var img = Image.FromFile(Server.MapPath(Url.Content("~/assets/img/nopic.png")));
                var ms = new MemoryStream();
                img.Save(ms, ImageFormat.Png);
                ms.Seek(0, SeekOrigin.Begin);
                radioModels.Pic = new byte[ms.Length];
                ms.Read(radioModels.Pic, 0, (int)ms.Length);
            }

            db.sys_Radio_Models.Add(radioModels);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        ViewBag.Manufacturer_Id = new SelectList(db.sys_Manufacturers, "Manufacturer_Id", "Manufacturer_Name_a", radioModels.Manufacturer_Id);
        return View(radioModels);
    }

那么，我的错误是什么......

由于