线程间操作无效: 从不是创建控件“richTextBox1”的线程访问它。(Socket),该怎么处理

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Windows.Forms;//添加引用using System.Net;using System.Net.Sockets;using System.Text;using System.Threading;namespace SocketServer{    public partial class Form1 : Form    {        Thread mythread;//创建线程        Socket socket;        int port = 8000;//定义侦听端口号                public Form1()//服务器端        {            InitializeComponent();        }        //获取本机IP地址        public static IPAddress GetServerIP()        {            IPHostEntry ieh = Dns.GetHostEntry(Dns.GetHostName());            return ieh.AddressList[0];        }        //监听        private void BeginListen()        {                        socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);                                    IPAddress ServerIp = GetServerIP();            IPEndPoint iep = new IPEndPoint(ServerIp, port);            socket.Bind(iep);            toolStripStatusLabel1.Text = iep.ToString() + "正在监听...";            byte[] byteMessage = new byte[100];             while (true)            {                try                {                    socket.Listen(5);                    Socket newSocket = socket.Accept();                    newSocket.Receive(byteMessage);                    string sTime = DateTime.Now.ToShortTimeString();                    string msg = sTime + "-" + "信息来自：";                    msg += newSocket.RemoteEndPoint.ToString() +" "+ Encoding.Default.GetString(byteMessage).Trim(new char[] {'\0'});                    [color=#FF0000]this.richTextBox1.AppendText(msg + "\r\n");[/color]                }                catch (SocketException ex)                {                    toolStripStatusLabel1.Text += ex.ToString();                }            }                    }        private void btn_Listen_Click(object sender, EventArgs e)        {            try            {                mythread = new Thread(new ThreadStart(BeginListen));                mythread.Start();            }            catch (System.Exception er)            {                MessageBox.Show(er.Message, "完成", MessageBoxButtons.OK, MessageBoxIcon.Stop);            }        }            }}

using System;using System.Windows.Forms;//添加引用using System.Net;using System.Net.Sockets;using System.Text;namespace SocketClient{    public partial class Form1 : Form    {        public Form1()//客户端        {            InitializeComponent();        }               private void Form1_Load(object sender, EventArgs e)        {            //得到本机地址            IPHostEntry ieh = Dns.GetHostEntry(Dns.GetHostName());            txtIP.Text = ieh.AddressList[0].ToString();        }        private void btn_Send_Click(object sender, EventArgs e)        {            BeginSend();        }        //发送信息        private void BeginSend()        {            string ip = txtIP.Text;            string port = txtPort.Text;            string msg = txtMsg.Text.Trim();                        Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);            IPAddress serverIp = IPAddress.Parse(ip);            int serverPort = Convert.ToInt32(port);            IPEndPoint iep = new IPEndPoint(serverIp, serverPort);                                    socket.Connect(iep);            byte[] byteMessage;            byteMessage = Encoding.ASCII.GetBytes(msg);            socket.Send(byteMessage);            socket.Shutdown(SocketShutdown.Both);            socket.Close();                    }            }}