C#窗体聊天小程序

Question

客户端第一次可以和服务器端正常连接和发送消息，把客户端断开连接，再重新连接后，服务器端就不能收到消息，这是什么问题？请指教！

Answer 1

如果是用winForm开发的，有可能socket抛出异常了或者服务器端窗体失去焦点了。

Answer 2

是这样的：
server：
private TcpListener listener;
        private TcpClient client;
        private Thread thread1;
        private void buttonStart_Click(object sender, EventArgs e)
        {
            this.buttonStart.Enabled = false;
            IPAddress ip = IPAddress.Parse(this.textBoxIP.Text);
            Int32 port = Int32.Parse(this.textBoxPort.Text);
            listener=new TcpListener(ip,port);
            listener.Start(10);
            client = listener.AcceptTcpClient();
                if (client.Connected)
                {
                    this.listBoxState.Items.Add("与客户" + client.Client.RemoteEndPoint.ToString() + "建立链接");
                    thread1 = new Thread(new ThreadStart(AcceptMessage));
                    thread1.Start();
                }
        }
        private void AcceptMessage()
        {
            while (true)
            {
                try
                {
                    NetworkStream netStream = client.GetStream();
                    byte[] buffer = new byte[1024];
                    int bytesRead = netStream.Read(buffer, 0, 1024);
                    string message = Encoding.Unicode.GetString(buffer, 0, bytesRead);
                    this.richTextBoxAccept.Rtf = message;
                }
                catch
                {
                    this.listBoxState.Items.Add("与客户断开连接");
                    break;
                }
            }
        }
        private void buttonSend_Click(object sender, EventArgs e)
        {
            string message = this.richTextBoxSend.Rtf;
            byte[] buffer =Encoding.Unicode.GetBytes(message);
            try
            {
                NetworkStream netStream = client.GetStream();
                netStream.Write(buffer, 0, buffer.Length);
                this.richTextBoxSend.Text = "";
            }
            catch
            {
                MessageBox.Show("无法发送!");
            }
        }        private void buttonStop_Click(object sender, EventArgs e)
        {
            this.buttonStart.Enabled = true;
            try
            {
                listener.Stop();
                listener = null;
                if (client.Connected)
                {
                    client.Close();
                    thread1.Abort();
                }
                this.listBoxState.Items.Add("停止监听");
            }
            catch
            {
                MessageBox.Show("监听尚未开始，关闭无效");
            }
        }
client：
 private TcpClient client;
        private Thread thread1;
        private void buttonRequest_Click(object sender, EventArgs e)
        {
            IPAddress ip = IPAddress.Parse(this.textBoxIP.Text);
            client = new TcpClient();
            Int32 port = Int32.Parse(this.textBoxPort.Text);
            try
            {
                client.Connect(ip, port);
            }
            catch
            {
                MessageBox.Show("与服务器连接失败");
            }
            this.buttonRequest.Enabled = false;
            this.listBoxState.Items.Add("与服务器连接成功");
            thread1 = new Thread(new ThreadStart(AcceptMessage));
            thread1.Start();        }
        private void AcceptMessage()
        {
            while (true)
            {
                try
                {
                    NetworkStream netStream = client.GetStream();
                    byte[] buffer = new byte[1024];
                    int bytesRead = netStream.Read(buffer, 0, 1024);
                    string message = Encoding.Unicode.GetString(buffer, 0, bytesRead);
                    this.richTextBoxReceive.Rtf =message;
                }
                catch
                {
                    this.listBoxState.Items.Add("与服务器断开连接");
                    break;
                }
            }
        }        private void buttonClose_Click(object sender, EventArgs e)
        {
            try
            {
                client.Close();
                this.listBoxState.Items.Add("与主机断开连接");
                thread1.Abort();            }
            catch
            {
                MessageBox.Show("尚未与主机连接，断开无效！");
            }
            this.buttonRequest.Enabled = true;        }
        private void buttonSend_Click(object sender, EventArgs e)
        {
            string message = this.richTextBoxSend.Rtf;
            byte[] buffer = Encoding.Unicode.GetBytes(message);
            try
            {
                NetworkStream netStream = client.GetStream();
                netStream.Write(buffer, 0, buffer.Length);
                this.richTextBoxSend.Rtf = "";
            }
            catch
            {
                MessageBox.Show("无法发送!");
            }
        }