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; }
 
        }
    }
}