但我不断收到“失败”错误消息框

Index.cshtml

<script src="~/Scripts/jquery-1.8.2.min.js"></script>
<script src="~/Scripts/jquery.unobtrusive-ajax.min.js"></script>
<h2>Files Upload</h2>
<script type="text/javascript">
$(function() {
    $("#form0").submit(function(event) {
        var dataString;
        event.preventDefault();
        var action = $("#form0").attr("action");
        if ($("#form0").attr("enctype") == "multipart/form-data") {
            //this only works in some browsers.
            //purpose? to submit files over ajax. because screw iframes.
            //also, we need to call .get(0) on the jQuery element to turn it into a regular DOM element so that FormData can use it.
            dataString = new FormData($("#form0").get(0));
            contentType = false;
            processData = false;
        } else {
            // regular form, do your own thing if you need it
        }
        $.ajax({
            type: "POST",
            url: action,
            data: dataString,
            dataType: "json", //change to your own, else read my note above on enabling the JsonValueProviderFactory in MVC
            contentType: contentType,
            processData: processData,
            success: function(data) {
                //BTW, data is one of the worst names you can make for a variable

            },
            error: function(jqXHR, textStatus, errorThrown) {
                //do your own thing
                alert("fail");
            }
        });
    }); //end .submit()
});
</script>
<div id="uploadDiv">
@Html.Action("Files", "Home")
</div>

@using (Ajax.BeginForm("Files", "Home", new AjaxOptions { UpdateTargetId = "uploadDiv", HttpMethod = "Post" }, new { enctype = "multipart/form-data", @id="form0"}))
{
<div>
    <div>Upload new file:
        <input type="file" name="file" /></div>
    <input type="submit" value="Save" />
</div>
}
<br />

控制者

public PartialViewResult Files(HttpPostedFileBase file)
    {
        IEnumerable<string> files;
        if ((file != null) && (file.ContentLength > 0))
        {
            string fileName = file.FileName;
            string saveLocation = @"D:\Files";
            string fullFilePath = Path.Combine(saveLocation, fileName);


            try
            {
                file.SaveAs(fullFilePath);
                FileInfo fileInfo = new FileInfo(fullFilePath);
                file.InputStream.Read(new byte[fileInfo.Length], 0, file.ContentLength);                    
            }
            catch (Exception e)
            {
                TempData["FileUpload"] = e.Message;
                return PartialView();
            }
            files = Directory.GetFiles(@"D:\Files\");
            return PartialView(files);
        }
        else
        {
            files = Directory.GetFiles(@"D:\Files\");
            return PartialView(files);
        }
    }

Files.cshtml

@model IEnumerable<string>

@foreach (string f in Model)
{
<p>@f</p>
}

Global.asax

ValueProviderFactories.Factories.Add(new JsonValueProviderFactory());