private void writeStream(NetworkStream nstream, string fileSavePath)
        {
            int  size = 0;
            long len  = 0;

            using (FileStream fs = new FileStream(fileSavePath, FileMode.Create, FileAccess.Write))
            {
                byte[] buffer = new byte[512];
                while ((size = nstream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    fs.Write(buffer, 0, size);
                    len          += size;
                    pbState.Value = (int)(len * 100 / filesize);
                    if (len == filesize)
                    {
                        break;
                    }
                }
                fs.Flush();
                nstream.Flush();
                nstream.Close();
                pbState.Value = 0;
            }
            ShwMsgForView.ShwMsgforView(lstbxMsgView, "文件接受成功" + fileSavePath);
        }
        private void btnBegin_Click(object sender, EventArgs e)
        {
            isStart           = true;
            btnCancel.Enabled = !(btnBegin.Enabled = false);

            listener = new TcpListener(IPAddress.Parse(cbIPBox.Text), int.Parse(tbPort.Text));
            listener.Start();
            ShwMsgForView.ShwMsgforView(lstbxMsgView, "服务器开始监听");
            Thread th = new Thread(ReceiveMsg);

            th.Start();
            th.IsBackground = true;
        }
        public void ReceiveMsg()
        {
            while (isStart)
            {
                try
                {
                    TcpClient client = listener.AcceptTcpClient();

                    if (client.Connected)
                    {
                        //向列表控件中添加一个客户端的Ip和端口,作为发送时客户的唯一标识
                        listbOnline.Items.Add(client.Client.RemoteEndPoint);
                        ShwMsgForView.ShwMsgforView(lstbxMsgView, "客户端连接成功" + client.Client.RemoteEndPoint.ToString());
                    }

                    NetworkStream stream = client.GetStream();


                    byte[] buffer = new byte[512];

                    //while (true)
                    //{
                    //    byte[] send = Encoding.ASCII.GetBytes("12121212");
                    //    stream.Write(send, 0, send.Length);
                    //    stream.Flush();
                    //    Thread.Sleep(100);
                    //}

                    int size;
                    while ((size = stream.Read(buffer, 0, buffer.Length)) > 0 || isStart)
                    {
                        byte[] recData = new byte[size];
                        Array.Copy(buffer, recData, size);
                        string   recsData = Encoding.ASCII.GetString(recData);
                        string[] rec      = recsData.Split(':');
                        if (rec.Length == 2)
                        {
                            filename = rec[0];
                            filesize = Convert.ToInt64(rec[1]);
                            byte[] send = Encoding.ASCII.GetBytes("OK");
                            stream.Write(send, 0, send.Length);
                            break;
                        }
                    }


                    if (stream != null && isStart)
                    {
                        SaveFileDialog sfd = new SaveFileDialog();
                        sfd.FileName = filename;
                        if (sfd.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
                        {
                            string fileSavePath = sfd.FileName;//获得用户保存文件的路径
                            writeStream(stream, fileSavePath);
                        }
                    }
                }
                catch (Exception ex)
                {
                    ShwMsgForView.ShwMsgforView(lstbxMsgView, "出现异常:" + ex.Message);
                }
            }
        }