asp.net 实现文件下载,该如何处理

asp.net 实现文件下载
if (File.Exists(fileName))
  {
  FileInfo file = new FileInfo(fileName);
  Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8"); //解决中文乱码
  Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(file.Name)); //解决中文文件名乱码  
  Response.AddHeader("Content-length", file.Length.ToString());
  Response.ContentType = "appliction/octet-stream";
  Response.WriteFile(fileName);
  Response.End();
  }
这段代码我在别的项目中用可以，但是在现在的项目中不管用了，出错了……

谁有这方面的经验，帮一下忙把！！！！！

[解决办法]
参考：
http://www.cnblogs.com/insus/articles/1411761.html
http://www.cnblogs.com/insus/articles/2003336.html
[解决办法]
参考我之前的下载代码:自己优化哈

C# code

using System;using System.Collections;using System.Data;using System.Linq;using System.Web;using System.Web.Services;using System.Web.Services.Protocols;using System.Xml.Linq;namespace Asiastar.NR.Ajax{    /// <summary>    /// $codebehindclassname$ 的摘要说明    /// </summary>    [WebService(Namespace = "http://tempuri.org/")]    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]    public class Handler1 : IHttpHandler    {        public void ProcessRequest(HttpContext context)        {            context.Response.ContentType = "text/plain";            string id = context.Request["id"].ToString();//获取资源的编号            System.IO.Stream iStream = null;            byte[] buffer = new Byte[10000];            int length;            long dataToRead;            NRBLL.File bf = new Asiastar.NRBLL.File();            Guid guid = new Guid(id);            if (bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"] != null)//判断数据库路径是否存在                     {                string filepath = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"].ToString();//获取资源完整路径                   D:\资源文件\600cc139-14cf-448e-9e50-daa972d35e01.jpg                string Oidfilename = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FileNam"].ToString();//旧文件名称                //string filename = System.IO.Path.GetFileName(filepath);//获取文件名称+后缀名            600cc139-14cf-448e-9e50-daa972d35e01.JPG                //int index = filepath.IndexOf(".");                //string filetype = filepath.Substring(index).ToLower();//后缀名                //string newfilename = Oidfilename;                //string filepath1 = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"].ToString().Substring(0,filepath.Length - 8);                try                {                    string fileName = HttpUtility.UrlEncode(System.Text.Encoding.UTF8.GetBytes(Oidfilename));//解码(注意这里2层解码)                    Oidfilename = Oidfilename.Replace("+", "%20");  //将“+”替换成“空格”                    iStream = new System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);                    dataToRead = iStream.Length;                    context.Response.ContentType = "application/octet-stream";                    context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(Oidfilename, System.Text.Encoding.UTF8));  //下载的时候下载原来的文件名称                    while (dataToRead > 0)                    {                        if (context.Response.IsClientConnected)                        {                            length = iStream.Read(buffer, 0, 10000);                            context.Response.OutputStream.Write(buffer, 0, length);                            context.Response.Flush();                            buffer = new Byte[10000];                            dataToRead = dataToRead - length;                        }                        else                        {                            dataToRead = -1;                        }                    }                }                catch (Exception ex)                {                    NR.Error.Log.LogType(ex.ToString());                }                finally                {                    if (iStream != null)                    {                        iStream.Close();                    }                }            }            else            {                NR.Error.Log.LogType("找不到文件!");            }        }        public bool IsReusable        {            get            {                return false;            }        }    }} 
 
[解决办法]
直接
C# code
 Response.Redirect
[解决办法]
http://hi.baidu.com/a_magic/blog/item/2d9c2811fe90f9cca7ef3fa8.html  

参考这个