C#线程中字符串没法被赋值？

C#线程中字符串无法被赋值？？？
private void button1_Click(object sender, EventArgs e)
  {
  threadServer = new Thread(new ThreadStart(accpServer));
  threadServer.IsBackground = true;
  threadServer.Start();
  }

  private void accpServer()
  {
  try
  {
  Control.CheckForIllegalCrossThreadCalls = false;//取消線程保護
  MyServer = new IPEndPoint(myIP, 9999);
  sock = new System.Net.Sockets.Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
  sock.Bind(MyServer);
  sock.Listen(50);
  while (true)
  {
  accSock = sock.Accept();
  if (accSock.Connected)
  {
  MessageBox.Show("有客户端成功连接");
  }

  Byte[] Rec = new Byte[64];
  NetworkStream netStream = new NetworkStream(accSock);
  netStream.Read(Rec, 0, Rec.Length);
  string rec1 =
  System.Text.Encoding.BigEndianUnicode.GetString(Rec);
  this.textBox1.Text = rec1;
 

  MessageBox.Show("参数1：" + rec1);//这里可以显示rec1的正确值，假如赋值为one

  if (textBox1.Text == "one" )//这个的判断结果是正确的，可以进入大括号
  {
  MessageBox.Show("接收成功");
  }
  if (rec1 == "one" )//但是这个却得出的判断结果是假，进不去大括号内部
  {
  MessageBox.Show("接收成功");
  }
  //}
  }
  catch (Exception err)
  {
  MessageBox.Show(err.ToString());
  }
  }


求各位帮帮忙看看这是怎么回事好吗，多谢了，困扰我一天了

[解决办法]
线程中访问界面控件需要做线程同步
参考如下代码：

C# code

public void DoWork(){    Thread.Sleep(5000);    Invoke(new EventHandler(DoInvoke));}private void DoInvoke(object sender, EventArgs e){    button1.Enabled = true;}private void button1_Click(object sender, EventArgs e){    button1.Enabled = false;    Thread vThread = new Thread(new ThreadStart(DoWork));    vThread.Start();}