关于ajaxFileUpload中dataType的问题

cqulyk 2015-03-06 11:00:44

html代码：上传一个文件到后台

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="MyWeb.WebForm1" %>



<!DOCTYPE html>



<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title></title>

    <script src="Scripts/jquery-1.8.2.js"></script>

    <script src="Scripts/ajaxfileupload.js"></script>

    <script type="text/javascript">

        $(function () {

            $("#btnUploadFile").click(function ()

            {

                alert("点击了");

                $.ajaxFileUpload({

                    url:"UploadFileHandler.ashx",

                    fileElementId: "fileToBeUpload",

                    dataType:"text",

                    //dataType:"json"

                    success: function (data)

                    {

                        alert(data);

                    },

                    error: function ()

                    {

                        alert("ERROR!");

                    }

                });

            });

        });

    </script>

</head>

<body>

   

        <div>

            <input type="file" id="fileToBeUpload" name="classfiedFile" />

            <input type="button" id="btnUploadFile" value="上传文件" />

        </div>

   

</body>

</html>

C#代码:存储文件,并返回{"returnCode":"0"}的json数据

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Web;



namespace MyWeb

{

    /// <summary>

    /// Summary description for UploadFileHandler

    /// </summary>

    public class UploadFileHandler : IHttpHandler

    {



        public void ProcessRequest(HttpContext context)

        {

            context.Response.ContentType = "text/plain";

            //context.Response.Write("Hello World");



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

             string uploadFileName = fileUploadedFromClient.FileName;

             string realFileName = Path.GetFileName(uploadFileName);

             realFileName = context.Request.MapPath("~/UploadFiles/" + Guid.NewGuid() + realFileName);

             fileUploadedFromClient.SaveAs(realFileName);



             context.Response.Write("{\"returnCode\":\"0\"}");

        }



        public bool IsReusable

        {

            get

            {

                return false;

            }

        }

    }

}

现在我的问题是:当文件在后台存储成功后,alert输出的结果并非是{"returnCode":"0"},而是<pre>{"returnCode":"0"}</pre>

我想知道为什么会是这个结果,怎样才能获得我想要的JSON格式.
当然把<pre></pre>人工去掉这种方案是可行的，但却会让人费解。

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