使用 C# ashx 进行值 Ajax 上传返回 '索引超出范围。必须为非负数且小于集合的大小。'错误

Question

我一直在使用 Valum 的 AJAX 上传脚本： http://valums.com/ajax-upload/

它满足了我的所有要求，而不是使用可怕的 swfupload flash 对象。我的 .ashx 脚本有 JS 点（为了爱和钱我无法调试）。这就是我在 .ashx 中的内容：

public class avatar : IHttpHandler, System.Web.SessionState.IRequiresSessionState {

public void ProcessRequest (HttpContext context) {
    //Debugger.Break();

string result = "{\"success\":true}";
    string path = HttpContext.Current.Server.MapPath("/client/vault/" + Helpers.CurrentClientHash(context.Session["SessionHash"].ToString()) + "/users/" + context.Session["SessionHash"].ToString() + "/");
    string saveLocation = string.Empty;
    string fileName = string.Empty;

    try
    {
        int length = 4096;
        int bytesRead = 0;
        Byte[] buffer = new Byte[length];

        //This works with Chrome/FF/Safari
        // get the name from qqfile url parameter here
        Debugger.Break();
        fileName = context.Request["params"];
        Debug.Write(fileName);

        saveLocation = context.Server.MapPath(path) + fileName;

        try
        {
            using (FileStream fileStream = new FileStream(saveLocation, FileMode.Create))
            {
                do
                {
                    bytesRead = context.Request.InputStream.Read(buffer, 0, length);
                    fileStream.Write(buffer, 0, bytesRead);
                }
                while (bytesRead > 0);
            }
        }
        catch (UnauthorizedAccessException ex)
        {
            // log error hinting to set the write permission of ASPNET or the identity accessing the code
            result = result.Replace("true","false, \"error\":" + ex.Message + " " + ex.InnerException + " " + ex.StackTrace.ToString());
        }
}
catch
{
    try
        {
            //This works with IE
            fileName = Path.GetFileName(context.Request.Files[0].FileName);
            saveLocation = context.Server.MapPath(path) + fileName;
            context.Request.Files[0].SaveAs(saveLocation);
        }
    catch (Exception ex)
        {
            result = result.Replace("true", "false, \"error\":" + ex.Message + " " + ex.InnerException);
        }
}
context.Response.Write(result);
}

public bool IsReusable {
    get {
        return false;
    }
}

}

这段代码是由 Valum 脚本的另一个用户友好提供的，因为它附带了 PHP 服务器端的东西。当我运行上传器时，我在控制台中看到以下内容：

[上传者]responseText = {“成功”：错误，“错误”：索引已超出 范围。必须为非负数且小于集合的大小。 参数名称：索引}

...上传当然失败了。我确信它与 FileStream 有关，但如果没有有意义的调试，我找不到问题。我认为这可能是因为该文件没有被 .ashx 拾取，但它位于参数中：

所以，如果可以的话，我有两个问题：

1. 任何人都可以立即看到我在哪里或为什么会遇到索引异常吗？
2. 如果没有，我该如何调试这个东西？我不能只从 VS2010 运行调试器，因为似乎没有加载任何 JS。我显然也不能直接进入 ashx...有什么想法吗？

帮助表示赞赏:)

Answer 1

不幸的是，我从未解决过这个问题。我卸载了 Valams 脚本并转到 Plupload。

Plupload 更简单，它支持 HTML5、Flash、Gears 和 BrowserPlus。最终这是理所当然的。以下是那些寻找 C# AJAX 上传器小部件的工作代码：

<script type="text/javascript" src="/js/jquery.min.js"></script>

    <script type="text/javascript" src="http://bp.yahooapis.com/2.4.21/browserplus-min.js"></script>
    <script type="text/javascript" src="/js/plupload.js"></script>

    <script type="text/javascript" src="/js/plupload.html5.js"></script>
    <script type="text/javascript" src="/js/plupload.gears.js"></script>
    <script type="text/javascript" src="/js/plupload.browserplus.js"></script>
    <script type="text/javascript" src="/js/plupload.silverlight.js"></script>
    <script type="text/javascript">
        // Custom example logic
        function $(id) {
            return document.getElementById(id);
        }


        var uploader = new plupload.Uploader({
            runtimes: 'gears,html5,silverlight,browserplus',
            browse_button: 'pickfiles',
            max_file_size: '2mb',
            multi_selection: false,
            url: '/components/uploadify/avatar.ashx',
            silverlight_xap_url: '/js/plupload.silverlight.xap',
            filters: [
                { title: "Image files", extensions: "jpg,gif,png" }
            ]
        });

        uploader.bind('Init', function (up, params) {
            $('filelist').innerHTML = "<div>Current runtime: " + params.runtime + "</div>";
        });

        uploader.bind('FilesAdded', function (up, files) {
            for (var i in files) {
                $('filelist').innerHTML += '<div id="' + files[i].id + '">' + files[i].name + ' (' + plupload.formatSize(files[i].size) + ') <b></b></div>';
            }
        });

        uploader.bind('UploadFile', function (up, file) {
            $('uploader').innerHTML += '<input type="hidden" name="file-' + file.id + '" value="' + file.name + '" />';
        });

        uploader.bind('UploadProgress', function (up, file) {
            $(file.id).getElementsByTagName('b')[0].innerHTML = '<span>' + file.percent + "%</span>";
        });

        uploader.bind('FileUploaded', function (up, file, obj) {
            alert("I've done uploading stuff...");

        });

        $('uploadfiles').onclick = function () {
            uploader.start();
            return false;
        };

        uploader.init();
</script>

以及 C# .ashx...

public class avatar : IHttpHandler, System.Web.SessionState.IRequiresSessionState {

    public void ProcessRequest (HttpContext context) {
        string path = "/a/path/to/someplace/";
        if (context.Request.Files.Count > 0)
        {
            int chunk = context.Request["chunk"] != null ? int.Parse(context.Request["chunk"]) : 0;
            string fileName = context.Request["name"] != null ? context.Request["name"] : string.Empty;

            HttpPostedFile fileUpload = context.Request.Files[0];

            var uploadPath = path;
            using (var fs = new FileStream(Path.Combine(uploadPath, fileName), chunk == 0 ? FileMode.Create : FileMode.Append))
            {
                var buffer = new byte[fileUpload.InputStream.Length];
                fileUpload.InputStream.Read(buffer, 0, buffer.Length);

                fs.Write(buffer, 0, buffer.Length);
            }
        }

    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}

可能值得注意的是，如果您想在 .ashx 中访问会话，您只需要添加 < code>SessionState.IRequiresSessionState 如图所示。

我希望大家觉得这有帮助:)

Answer 2

我使用了 Syed Basher 在他的 中提供的 ASHX 处理程序博客。它工作完美。

  public void ProcessRequest(HttpContext context)
  {
      const string path = "Capture/Images";
      String filename = HttpContext.Current.Request.Headers["X-File-Name"];
      if (string.IsNullOrEmpty(filename) && HttpContext.Current.Request.Files.Count <= 0)
      {
          context.Response.Write("{success:false}");
      }
      else
      {
          string mapPath = HttpContext.Current.Server.MapPath(path);
          if (Directory.Exists(mapPath) == false)
          {
              Directory.CreateDirectory(mapPath);
          }
          if (filename == null)
          {
              //This work for IE
              try
              {
                  HttpPostedFile uploadedfile = context.Request.Files[0];
                  filename = uploadedfile.FileName;
                  uploadedfile.SaveAs(mapPath + "\\" + filename);
                  context.Response.Write("{success:true, name:\"" + filename + "\", path:\"" + path + "/" + filename + "\"}");
              }
              catch (Exception)
              {
                  context.Response.Write("{success:false}");
              }
          }
          else
          {
              //This work for Firefox and Chrome.
              FileStream fileStream = new FileStream(mapPath + "\\" + filename, FileMode.OpenOrCreate);
              try
              {
                  Stream inputStream = HttpContext.Current.Request.InputStream;
                  inputStream.CopyTo(fileStream);
                  context.Response.Write("{success:true, name:\"" + filename + "\", path:\"" + path + "/" + filename + "\"}");
              }
              catch (Exception)
              {
                  context.Response.Write("{success:false}");
              }
              finally
              {
                  fileStream.Close();
              }
          }
      }
  } 

Answer 3

我看到的唯一会产生这些结果的异常处理程序位于“这适用于 IE”块。该块中引用的唯一索引是 Files[0]。

我建议在第一个 try/catch 中添加一个 catch(Exception ex) 来确定为什么适用于 Safari 的代码不适用于 IE。另一件需要注意的事情是，您正在读取所有浏览器的流，然后尝试仅为 IE 重新读取流。这需要将流重置到位置 0。

查看此服务器端脚本是否适用于所有浏览器：

using System;
using System.Web;
using System.IO;
public class Upload : IHttpHandler 
{   
    public void ProcessRequest(HttpContext context) 
    {   
        string path = HttpContext.Current.Server.MapPath("/client/vault/" 
            + Helpers.CurrentClientHash(context.Session["SessionHash"].ToString()) 
            + "/users/" + context.Session["SessionHash"].ToString() 
            + "/");

        HttpPostedFile oFile = 
                    context.Request.Files[context.Request.Headers["X-File-Name"]]; 

        if (!Directory.Exists(path)) Directory.CreateDirectory(path);       
        oFile.SaveAs(path + oFile.FileName);     

        context.Response.Write("1");   
    }   
    public bool IsReusable 
    {      
        get { return true; }   
    }
}