Asp.net mvc 4 通过ajax将值传递给具有空httppostedbasefile的控制器操作

我的剃须刀html：

 @using (Html.BeginForm("CreateTestinomialPage", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        @Html.AntiForgeryToken()
        @Html.ValidationSummary(true)

        <fieldset>
            <legend>Fill Form</legend>
            @Html.HiddenFor(m => m.PostedTypeId)
            <div class="editor-label">
                @Html.DisplayName("Image Upload")
            </div>
            <div class="editor-field" >
             @*<input type="file" name="file" id="file" />*@
               @Html.TextBoxFor(m => m.file,new{type="file"})
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.Message)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.Message)
                @Html.ValidationMessageFor(model => model.Message)
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.Postedby)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.Postedby)
                @Html.ValidationMessageFor(model => model.Postedby)
            </div>

            <p>
                <input type="submit" value="Create" />

            </p>
            <div id="result"></div>
        </fieldset>
    }

---

存在controllerAction null httppostedbasefile..

文件无法通过ajax上载

<script type="text/javascript">

    $(function () {
        $('form').submit(function () {
            if ($(this).valid()) {
                $.ajax({
                    url: this.action,
                    type: this.method,
                    data: $(this).serialize(),

                    success: function (result) {

                        $('#result').html(result);
                    },
                    complete: function () {
                        $('form').each(function () {
                            this.reset();   //Here form fields will be cleared.
                        });
                    },

                });

            }
            return false;
        });
    });
 </script>

[HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult CreateTestinomialPage(TestinomialsModels models,HttpPostedFileBase  file)
        {
            if (ModelState.IsValid)
            {

                if (file  == null)
                {
                    ModelState.AddModelError("File", "Please Upload Your file");
                }
                else if (file.ContentLength > 0)
                {
                    int maxcontentlength = 1024 * 1024 * 3;
                    string[] AllowedExtension = new string[] { ".jpg", ".gif", ".png" };
                    if (!AllowedExtension.Contains(file.FileName.Substring(file.FileName.LastIndexOf('.'))))
                    {
                        ModelState.AddModelError("File", "Please file of type: " + string.Join(", ", AllowedExtension));
                    }
                    else if (file.ContentLength > maxcontentlength)
                    {
                        ModelState.AddModelError("File", "Your file is too large, maximum allowed size is: " + maxcontentlength + " MB");
                    }
                    else
                    {
                        var filename = Path.GetFileName(models.file.FileName);
                        models.ImagePath = ConfigurationManager.AppSettings["ImagesavePath"].ToString() + filename;
                        postservices.AddTestinomailPost(models);
                        var path = Path.Combine(Server.MapPath("~/Content/Upload/Images"), filename);
                        models.file.SaveAs(path);

                        return Content("Successfully Submiited");
                    }

                }
            }

            return Content("An error occur while saved Plese try again..");


        }