c# tcpclient-tpclistener文件传送

Question

客户端：
  DialogResult dr=openFileDialog1.ShowDialog();
           if (DialogResult.OK == dr)
           {
               Stream st = openFileDialog1.OpenFile();
               byte[] by = new byte[1000];
               int count = Convert.ToInt32(st.Length);//获取文件流长度
               while (count != 0)//循环写入
               {
                   if (count - by.Length < 0)//判断流长度 如果小于1000就按照剩余流量写入 否则按1000写入
                   {
                       
                       st.Read(by, 0, count);//读取流 按照剩余流量读取
                       ns.Write(by, 0, count);//写入网络流中
                       st.Flush();//刷新文件流
                       ns.Flush();//刷新网络流
                       count = 0;//已经读取完毕 设置为0 停止循环
                   }
                   else
                   {
                       count = count - by.Length;//将原有流减去已经发送的流
                       st.Read(by, 0, by.Length);//读取流 
                       ns.Write(by, 0, by.Length);//写入网络流中
                       st.Flush();
                       ns.Flush();
                   }               }
               st.Close();
               MessageBox.Show("传送完毕");
           }
服务器：
 if (ns.DataAvailable)
                    {
                        DialogResult rs = saveFileDialog1.ShowDialog();
                        if (DialogResult.OK == rs)
                        {
                            byte[] by = new byte[1000];
                            int count = 0;
                            FileStream ft = new FileStream(saveFileDialog1.FileName, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
                            do//循环读取 直到网络流为0
                            {                                count = cl.Available;//检查可以数据流
                                if (count < by.Length)//判断流长度 如何小于数组长度就按照count的长度读取
                                {   //和上面的差不多意思
                                    ns.Read(by, 0, count );
                                    ft.Write(by, 0, count );
                                    ns.Flush();
                                    ft.Flush();
                                  
                                }
                                else
                                {
                                    ns.Read(by, 0, by.Length);
                                    ft.Write(by, 0, by.Length);
                                    ns.Flush();
                                    ft.Flush();                                }
                            } while (count != 0);                            ft.Close();
                            MessageBox.Show("接受完毕！");
                        }
大家觉得这个代码怎么样！弊端在哪里？（不能够传送大文件）发表一下你们的意见吧！