1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Threading.Tasks;
 9 using System.Windows.Forms;
10 using System.Net;
11 using System.Net.Sockets;
12 
13 namespace WindowsFormsApplication1
14 {
15     public partial class Form1 : Form
16     {
17         public Form1()
18         {
19             InitializeComponent();
20         }
21 
22         private void button1_Click(object sender, EventArgs e)
23         {
24             TcpListener tcplistener = null;
25             IPAddress ipaddress = IPAddress.Parse(textBox1.Text);
26             int port = Convert.ToInt32(textBox2.Text);
27             tcplistener = new TcpListener(ipaddress, port);
28             tcplistener.Start();
29             richTextBox1.Text = "等待连接。。。\n";
30             TcpClient tcpclient = null;
31             if (tcplistener.Pending())
32                 tcpclient = tcplistener.AcceptTcpClient();
33             else
34                 tcpclient = new TcpClient(textBox1.Text, port);
35             richTextBox1.Text += "连接成功！！\n";
36             tcpclient.Close();
37             tcplistener.Stop();
38         }
39 
40         private void button2_Click(object sender, EventArgs e)
41         {
42             richTextBox2.Text = string.Empty;
43             UdpClient udpclient = new UdpClient(Convert.ToInt32(textBox4.Text));
44             udpclient.Connect(textBox3.Text, Convert.ToInt32(textBox4.Text));
45             Byte[] sendBytes = Encoding.Default.GetBytes(textBox5.Text);
46             udpclient.Send(sendBytes, sendBytes.Length);
47             IPEndPoint ipendpoint = new IPEndPoint(IPAddress.Any, 0);
48             Byte[] receiveBytes = udpclient.Receive(ref ipendpoint);
49             string returnData = Encoding.Default.GetString(receiveBytes);
50             richTextBox2.Text = "接收到的信息： " + returnData.ToString();
51             richTextBox2.Text += "\n 这条信息来自主机 " + ipendpoint.Address.ToString()
52                 + " 上的 " + ipendpoint.Port.ToString()  +"端口";
53         }
54     }
55 }