F6 Team

        System.IO.Stream iStream = null;

        //以10K為單位暫存:
        byte[] buffer = new Byte[10000];

        int length;

        long dataToRead;

        // 制定文件路徑.
        string filepath = Server.MapPath("~/aaa.rar");

        //  得到文件名.
        string filename = System.IO.Path.GetFileName(filepath);

        try
        ...{
            // 打開文件.
            iStream = new System.IO.FileStream(filepath, System.IO.FileMode.Open,
                        System.IO.FileAccess.Read, System.IO.FileShare.Read);


            // 得到文件大小:
            dataToRead = iStream.Length;

            Response.ContentType = "application/x-rar-compressed";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(filename));

            while (dataToRead > 0)
            ...{
                //保証client連接
                if (Response.IsClientConnected)
                ...{
                    length = iStream.Read(buffer, 0, 10000);

                    Response.OutputStream.Write(buffer, 0, length);

                    Response.Flush();

                    buffer = new Byte[10000];
                    dataToRead = dataToRead - length;
                }
                else
                ...{
                    //结束循環
                    dataToRead = -1;
                }
            }
        }
        catch (Exception ex)
        ...{
            // error
            Response.Write("Error : " + ex.Message);
        }
        finally
        ...{
            if (iStream != null)
            ...{
                //關閉文件
                iStream.Close();
            }
        }