C#中线程中设置另一个线程的控件属性

窗口中有两个控件，一个richTextBox名字为rtxt_main，另外一个为一个按钮（Button）名字为button01，程序启动后点击按钮将启动一个线程，在线程中使用委托技术更新richTextBox的文字，关键代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public int port = 8192;
        public Form1()
        {
            InitializeComponent();           
        }
        public delegate void delegateHandler(String str);                     //定义一个委托

        private void Form1_Load(object sender, EventArgs e)
        {
            this.rtxt_main.AppendText("Server is start...\n");
        }

        private void setShow(String strTemp)  {
            if (this.InvokeRequired)
            {
                delegateHandler delegateSetText = new delegateHandler(setShow);  //声明回调函数对象     
                this.Invoke(delegateSetText, new object[] { strTemp });          //调用自己              
            }
            else {
                this.rtxt_main.AppendText(strTemp);                              //内部调用
            }
        }

        private void TcpServer() {
            TcpListener listener = new TcpListener(IPAddress.Any, port);
            listener.Start();
            setShow("Server running...\n");
            while (true)
            {
                const int bufferSize = 8155;
                TcpClient client = listener.AcceptTcpClient();
                NetworkStream clientStream = client.GetStream();
                byte[] buffer = new byte[bufferSize];
                int readcount = 0;
                readcount = clientStream.Read(buffer, 0, bufferSize);
                String result = Encoding.UTF8.GetString(buffer).Substring(0, readcount);
                setShow(result);
                clientStream.Close();
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Thread t = new Thread(TcpServer);
            t.Start();
        }
    }
}

运行效果如下：程序为一个TCP客户端程序，TCP部分还未验证，有待核实更新。。。