第二连接上的ssh.net sshoperation timeout

Question

我要以第二种形式连接到SSH。当我第一次执行Connect（）命令时，一切正常。如果我关闭表单并尝试重新连接，则在调用Connect（）之后将获得SshoperationTimeout。

ConnectionInfo connNfo = new ConnectionInfo(ip, 22, username,
               new AuthenticationMethod[]{
                    // Pasword based Authentication
                    new PasswordAuthenticationMethod(username,password),
               }
            )

client = new SshClient(connNfo);
try
 { 
      client.Connect();
 }
 catch 
 {
      MessageBox.Show("Error","Error",MessageBoxButtons.OK,MessageBoxIcon.Error);
      this.Close();
      return;
 }

shellStreamSSH = client.CreateShellStream("vt-100", 80, 60, 800, 600, 65536);
shellThread = new Thread(() => recvSSHData(shellStreamSSH));
shellThread.Start();

的控制台方法输出的方法：

void recvSSHData(ShellStream shellStreamSSH)
        {
            while (true)
            {
                try
                {
                    if (shellStreamSSH != null && shellStreamSSH.DataAvailable)
                    {
                        string strData = shellStreamSSH.Read();
                        appendRichTextBox(strData);
                    }
                }
                catch
                {}

                Thread.Sleep(200);
            }
        }

打印称为关闭和断开SSH客户端

private void Form3_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (shellThread != null && shellThread.IsAlive)
            {
                shellThread.Abort(); 
            }

            if (shellStreamSSH != null)
            { 
                shellStreamSSH.Close();
                shellStreamSSH.Dispose();
            }

            if (client != null && client.IsConnected)
            {
                client.Disconnect();
                client.Dispose();
            }
        }