AjaxFileUpload + *.ashx 文件上传在IE8.0(XP,VS2010，Development Server)下的注意

ashx,中返回类型设置成 json,plain时，返回的Json代码解析都出错，调试发现实际返回的除了json字符串外还有，其他html或xml导致无法解析成json对象

        function UploadFile(elmFlag) {
            $.ajaxFileUpload({
                url: '/FileUpload.ashx',
                secureuri: false,
                fileElementId: "fu" + elmFlag,
                dataType: "json",
                success: function (data, status) {
                    if (data.Code == 200) {
                        alert( unescape(data.Name));
                    } else {
                        alert( unescape(data.Msg));
                    }
                    $("#c_" + elmFlag).empty();
                    $("#c_" + elmFlag).append("<input type='file' name='fu" + elmFlag + "' id='fu" + elmFlag + "' onchange=\"UploadFile('" + elmFlag + "')\"   />");

                },
                error: function (data, status, e) {
                    alert("错误：上传组件错误，请检察网络!");
                }
            });

        }

 服务器端

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Serialization;
using System.IO;
using System.Web.Hosting;
using F.Studio.Common;

using Microsoft.Practices.Unity;
using JLMFG.Doc.BLL;
using JLMFG.Doc.Domain;

namespace JLMFG.Doc.Web
{
    /// <summary>
    /// FileUpload 的摘要说明
    /// </summary>
    public class FileUpload : IHttpHandler,IBuildUp
    {

        static readonly string C_FileRoot = "/Files/";

        [Dependency]
        public doc_DocManager DocMgr { get; set; }

        private HttpRequest Request { get;  set; }
        private HttpResponse Response { get; set; }
        private JavaScriptSerializer Serializer { get; set; }
        public void ProcessRequest(HttpContext context)
        {
            Request = context.Request;
            Response = context.Response;
            Serializer = new JavaScriptSerializer();

            Response.ContentType = "text/html";
            Response.Expires = -1;

            try
            {

                if (Request.Files.Count <= 0) throw new Exception("没有文件上传!");
             
                SaveFile();
            }
            catch (Exception ex)
            {
                var resp=new UploadResponse(){Code=400,Msg=StringHelper.Escape(ex.Message)};
                Response.Write(Serializer.Serialize(resp));
            }


            Response.End();
           
        }

        private void  SaveFile()
        {

            var file = Request.Files[0];
            var ext = Path.GetExtension(file.FileName);


            //确保目录存在
            string path =  C_FileRoot + DateTime.Now.ToString("yyyy-MM-dd") + "/";

            if (!Directory.Exists( HostingEnvironment.MapPath(path)))
            {
                Directory.CreateDirectory(HostingEnvironment.MapPath(path));
            }
            //合成文件名
            var filename= path + Guid.NewGuid().ToString("N").Substring(0,8) + ext;

            var resp = new UploadResponse();
            resp.MIME = file.ContentType;
            resp.Size = file.ContentLength / 1024;
            resp.Name =StringHelper.Escape( Path.GetFileNameWithoutExtension(file.FileName));
            resp.Path =StringHelper.Escape( filename);
            resp.Code = 200;
            resp.Msg = "Success";

            //保持文件
            file.SaveAs(System.Web.Hosting.HostingEnvironment.MapPath(filename));

     
            Response.Write(Serializer.Serialize(resp));
        }



        public bool IsReusable
        {
            get
            {
                return false;
            }
        }


        public class UploadResponse
        {
            public int Code { get; set; }
            public string Msg { get; set; }
            public string Path { get; set; }
            public string Name { get; set; }
            public long Size { get; set; }
            public string MIME { get; set; }

        }
    }
}