需要帮助使用 ASP.NET MVC2 调试基于 XHR 的 Ajax 图像上传

Question

我正在尝试使用 http://valums.com/ajax-upload/ 中找到的脚本

我的控制器如下

using System;
using System.IO;
using System.Text.RegularExpressions;
using System.Web;
using System.Web.Hosting;
using System.Web.Mvc;
using MHNHub.Areas.ViewModels;
using MHNHub.Models;
using MHNHub.ViewModels;

namespace MHNHub.Areas.Admin.Controllers
{
    [Authorize(Roles = "Administrator")]
    public class ImageController : Controller
    {

        private MHNHubEntities _entities = new MHNHubEntities();

        //
        // GET: /Image/
        [AcceptVerbs(HttpVerbs.Get)]
        public ActionResult ImageUploader()
        {
            var viewModel = new ImageViewModel()
            {
                Image = new Image()
            };

            return PartialView(viewModel);
        }

        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult ImageUploader(Image image)
        {
            try
            {
                _entities.Images.AddObject(image);
                _entities.SaveChanges();

                return RedirectToAction("Index", "Product");
            }
            catch (Exception ex)
            {
                var viewModel = new ImageViewModel()
                                {
                                    Image = image,
                                    HasError = true,
                                    ErrorMessage = ex.Message
                                };
                return PartialView(viewModel);

            }
        }

        private string _uploadsFolder = HostingEnvironment.MapPath("~/App_Data/Files");

        public Guid Upload(HttpPostedFileBase fileBase)
        {
            var identifier = Guid.NewGuid();
            fileBase.SaveAs(GetDiskLocation(identifier));
            return identifier;
        }

        private string GetDiskLocation(Guid identifier)
        {
            return Path.Combine(_uploadsFolder, identifier.ToString());
        }

    }

}

我有一个像这样的部分视图

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<MHNHub.ViewModels.ImageViewModel>" %>

<script type="text/javascript">
    $(function () {
        $("#imagedialog").dialog({
            bgiframe: true,
            height: 170,
            width: 430,
            modal: true,
            autoOpen: false,
            resizable: true
        })
    });

    $(document).ready(function createUploader() {
        var uploader = new qq.FileUploader({
            element: document.getElementById('fileuploader'),
            action: '/Image/Upload/',
            name: 'name'
        });

    });

</script>    

<div id="imagedialog" title="Upload Image">

                <div id="fileuploader">

                </div>
                <h6>Drag and drop files supported in Firefox and Google Chrome with javascript enabled.</h6> 
                    <noscript>
                         <form action="/image/upload" enctype="multipart/form-data" method="post">
                            Select a file: <input type="file" name="photo" id="photo" />   

                            <input type="submit" value="Upload" name="submit"/>
                        </form>
                    </noscript>


</div>

<div class="editor-field">
    <img src="<%: Model.Image.FileName %>" />
    <%: Html.TextBoxFor(model => model.Image.FileName) %>
    <%: Html.ValidationMessageFor(model => model.Image.FileName)%>
    <a href="#" onclick="jQuery('#imagedialog').dialog('open'); return false">Upload Image</a>
</div>

我在母版页上正确链接了 fileuploader.js 和 fileuploader.css，上传器显示正确，甚至调用我的操作，但 HttpPostedFileBase 为空并且上传操作抛出异常。关于我应该做什么有什么见解吗？

编辑

所以我发现使用 firebug 发送 XmlHttpRequest。我该如何在上传操作中处理这个问题？

Answer 1

您在控制器操作中获得空参数的原因是因为此插件不会向服务器发送 multipart/form-data 请求。相反，它发送 application/octet-stream 内容类型请求标头，并将文件内容直接写入请求流，并将参数 ?qqfile 附加到包含文件名的 URL 。因此，如果您想在控制器上检索此内容，您将需要直接读取流：

[HttpPost]
public ActionResult Upload(string qqfile)
{
    using (var reader = new BinaryReader(Request.InputStream))
    {
        // This will contain the uploaded file data and the qqfile the name
        byte[] file = reader.ReadBytes((int)Request.InputStream.Length);
    }
    return View();
}

如果您选择多个文件，则插件只需向服务器发送多个请求，这样就可以工作。

此外，如果您想处理大于 int.MaxValue 的文件，您将必须从请求流中读取块并直接写入输出流，而不是将整个文件加载到内存缓冲区中：

using (var outputStream = File.Create(qqfile))
{
    const int chunkSize = 2 * 1024; // 2KB
    byte[] buffer = new byte[chunkSize];
    int bytesRead;
    while ((bytesRead = Request.InputStream.Read(buffer, 0, buffer.Length)) > 0)
    {
        outputStream.Write(buffer, 0, bytesRead);
    }
}

备注：从 document.ready 中删除 createUploader 函数名称。那里应该是一个匿名函数。您甚至可以将其与您已经必须设置模式对话框的 $(function() { ... }); 合并。