文件下载！！！！


///<summary>
        /// 输出硬盘文件，提供下载 支持大文件、续传、速度限制、资源占用小
        /// </summary>
        /// <param name="MyRequest">Page.Request对象</param>
        /// <param name="MyResponse">Page.Response对象</param>
        /// <param name="MyFileName">下载文件名</param>
        /// <param name="MyFullPath">带文件名下载路径</param>
        /// <param name="MySpeed">每秒允许下载的字节数</param>
        /// <returns>True Or False</returns>
        public bool ResponseFile(HttpRequest MyRequest, HttpResponse MyResponse, string MyFileName, string MyFullPath, long MySpeed)
        {
            try
            {
                FileStream myFile = new FileStream(MyFullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
                BinaryReader br = new BinaryReader(myFile);                try
                {
                    MyResponse.AddHeader("Accept-Ranges", "bytes");
                    MyResponse.Buffer = false;                    long fileLength = myFile.Length;
                    long startBytes = 0;
                    int pack = 10240;     //10K bytes
                    int sleep = (int)Math.Floor(1000.0 * pack / MySpeed) + 1;                    if (MyRequest.Headers["Range"] != null)
                    {
                        MyResponse.StatusCode = 206;
                        string[] range = MyRequest.Headers["Range"].Split(new char[] { '=', '-' });
                        startBytes = Convert.ToInt64(range[1]);
                    }                    MyResponse.AddHeader("Content-Length", (fileLength - startBytes).ToString());                    if ((startBytes != 0))
                    {
                        MyResponse.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));
                    }                    MyResponse.AddHeader("Connection", "Keep-Alive");
                    MyResponse.ContentType = "application/octet-stream";
                    MyResponse.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(MyFileName, System.Text.Encoding.UTF8));
                    br.BaseStream.Seek(startBytes, SeekOrigin.Begin);                    int maxCount = (int)Math.Floor(1.0 * (fileLength - startBytes) / pack) + 1;                    for (int i = 0; i <= maxCount; i++)
                    {
                        if ((MyResponse.IsClientConnected))
                        {
                            MyResponse.BinaryWrite(br.ReadBytes(pack));
                            System.Threading.Thread.Sleep(sleep);
                        }
                        else
                        {
                            i = maxCount;
                        }
                    }
                }
                catch
                {
                    return false;
                }
                finally
                {
                    br.Close(); myFile.Close();
                }
            }
            catch
            {
                return false;
            }
            return true;
        }