C# udp 文本内容提取

using System;

using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace udp
{
public partial class Form1 : Form
{
private UdpClient sendUdpClient;
private UdpClient receiveUpdClient;
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
sendUdpClient = new UdpClient();
receiveUpdClient = new UdpClient(9999);
this.txtSendText.Focus();

Control.CheckForIllegalCrossThreadCalls = false;
Thread thread = new Thread(receive);
thread.Start();
}

private void receive()
{

while (true)
{
Socket socket = receiveUpdClient.Client;
byte[] b = new byte[1024];
socket.Receive(b);
////IPAddress ip = ((System.Net.IPEndPoint)socket.RemoteEndPoint).Port;
//MessageBox.Show(((System.Net.IPEndPoint)socket.RemoteEndPoint).Port + "");
string message = Encoding.Default.GetString(b);
this.richTextBox1.Text += "\n" + message;

}

}
private void btnsend_Click(object sender, EventArgs e)
{
byte[] sendbytes = Encoding.Default.GetBytes(this.txtSendText.Text);
sendUdpClient.Send(sendbytes, sendbytes.Length, "192.168.23.138", 9999);
}
int a = 0;
private void btnload_Click(object sender, EventArgs e)
{
FileStream fs = File.OpenRead("E:\\汤姆叔叔的小屋.txt");

byte[] b = new byte[1024];
fs.Position = 1024*a;
fs.Read(b, 0, b.Length);

string text = Encoding.Default.GetString(b);
this.richTextBox1.Text = text;
a++;
}
}
}