asp.net下载，支持中文名，断点续传，控制单线程下载速度

参考：http://blog.youkuaiyun.com/Teng_s2000/archive/2005/10/21/510857.aspx

　　　http://www.cnblogs.com/bestcomy/archive/2004/08/10/31950.html

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;

namespace lianxi
{
    public class Download
    {
        public Download()
        {
        }
        public static void DownloadFile(HttpResponse Response, HttpRequest Request, string filepath, int speed)
        {

            if (!File.Exists(filepath))
            {
                Response.StatusCode = 404; //http状态代码，具体请看http://hi.baidu.com/%C3%AB%CE%D1/blog/item/7066a154993750133b2935ab.html
                return;
            }
            string name = Path.GetFileName(filepath); //获取文件名
            int packSize = 10240;
            byte[] buffer = new byte[packSize];
            long fileLength;
            long startByets = 0;
            FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            BinaryReader br = new BinaryReader(fs);
            fileLength = fs.Length;
            int sleep = (int)Math.Ceiling(1000.0 * packSize / speed); //用于单线程控制下载速度
            try
            {
                Response.Clear();
                Response.ClearHeaders();
                Response.Buffer = false;
                if (Request.Headers["Range"] != null)
                {
                    Response.StatusCode = 206; //这个续传是必备的
                    startByets = long.Parse(Request.Headers["Range"].Replace("bytes=", "").Replace("-", "")); //获取客户端已经下载的字节数
                }
                if (startByets != 0)
                {
                    Response.AddHeader("Content-Range", string.Format("bytes {0}-{1}/{2}", startByets, fileLength - 1, fileLength)); //续传必备，表示客户端从哪个字节开始下载，到哪个字节结束下载，具体请看http://hi.baidu.com/%C3%AB%CE%D1/blog/item/a630dfd3c18dbbd3a8ec9afc.html中的“Content-Range”，注意“fileLength - 1”，这是有点像数组，用文件的长度-1就可以得到数组的最后字节了。
                }
                Response.AddHeader("Content-Length", fileLength.ToString()); //告诉客户端所要下载文件的长度
                Response.AddHeader("Accept-Ranges", "bytes"); //续传必备
                Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(name, System.Text.Encoding.UTF8));//用于支持英文文件名
                Response.ContentType = "application/octet-stream"; //一般是这个，这个请看http://baike.baidu.com/view/160611.htm（MIME百科）
                Response.ContentEncoding = System.Text.Encoding.UTF8;
                fs.Seek(startByets, SeekOrigin.Begin);//设置文件流的起点位置
                int maxCount = (int)Math.Ceiling((fileLength - startByets + 0.0) / packSize);
                for (int i = 0; i < maxCount && Response.IsClientConnected; i++)
                {
                    //int length = fs.Read(buffer, 0, packSize);
                    //Response.OutputStream.Write(buffer, 0, packSize);
                    Response.BinaryWrite(br.ReadBytes(packSize));
                    Response.Flush();
                    if (sleep > 0) System.Threading.Thread.Sleep(sleep);
                }
            }
            catch (Exception ex)
            {
                Response.Write(ex.Message);
            }
            finally
            {
                fs.Close();
            }
        }
           
    }
}

2

// 输出硬盘文件，提供下载
  // 输入参数 _Request: Page.Request对象，  _Response: Page.Response对象， _fileName: 下载文件名， _fullPath: 带文件名下载路径， _speed 每秒允许下载的字节数
  // 返回是否成功
  public static bool ResponseFile(HttpRequest _Request,HttpResponse _Response,string _fileName,string _fullPath, long _speed)
  {
   try
   {
    FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
    BinaryReader br = new BinaryReader(myFile);
    try
    {
     _Response.AddHeader("Accept-Ranges", "bytes");
     _Response.Buffer = false;
     long fileLength = myFile.Length;
     long startBytes = 0;
     
     int pack = 10240; //10K bytes
     //int sleep = 200;   //每秒5次   即5*10K bytes每秒
     int sleep = (int)Math.Floor(1000 * pack / _speed) + 1;
     if (_Request.Headers["Range"] != null)
     {
      _Response.StatusCode = 206;
      string[] range = _Request.Headers["Range"].Split(new char[] {'=', '-'});
      startBytes = Convert.ToInt64(range[1]);
     }
     _Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
     if (startBytes != 0)
     {
      _Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength-1, fileLength));
     }
     _Response.AddHeader("Connection", "Keep-Alive");
     _Response.ContentType = "application/octet-stream";
     _Response.AddHeader("Content-Disposition","attachment;filename=" + HttpUtility.UrlEncode(_fileName,System.Text.Encoding.UTF8) );
 
     br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
     int maxCount = (int) Math.Floor((fileLength - startBytes) / pack) + 1;

     for (int i = 0; i < maxCount; i++)
     {
      if (_Response.IsClientConnected)
      {
       _Response.BinaryWrite(br.ReadBytes(pack));
       Thread.Sleep(sleep);
      }
      else
      {
       i=maxCount; 
      }
     }
    }
    catch
    {
     return false;
    }
    finally
    {
     br.Close();
     myFile.Close();
    }
   }
   catch
   {
    return false;
   }
   return true;
  }


调用例

   Page.Response.Clear();
      
   bool success = ResponseFile(Page.Request, Page.Response, "filename", @"C:/download.date", 1024000);
   
   if(!success)
    Response.Write("下载文件出错！");

   Page.Response.End();