public void backConnect( IPAddress backIP,int backPort,string negativeID)

        {

            try

            {

                TcpClient tcp = new TcpClient();//申明tcp客户端

                tcp.Connect(backIP,backPort);//连接tcp



                Thread.Sleep(1000);// 延时操作

                

                if (tcp != null)

                {

                    formDboper.listboxDboper.Items.Add("返回标示字TCP连接" + backIP + "成功!");

                    formDboper.listboxDboper.TopIndex = formDboper.listboxDboper.Items.Count - 1;//顶端显示最后一行

                   

                    ns = tcp.GetStream();

                    Byte[] sendBytes = Encoding.ASCII.GetBytes(negativeID);//将negativeID以ASCII形式编码成Bytes类型的字节流数组

                    ns.Write(sendBytes, 0, sendBytes.Length);



                    formDboper.listboxDboper.Items.Add("标示字"+negativeID+"已返回!");

                    formDboper.listboxDboper.TopIndex = formDboper.listboxDboper.Items.Count - 1;//顶端显示最后一行



                    ns.Flush();

                    ns.Close();

                }