Udp通信 暑期学习笔记（三）

有了笔记（二）中的积累，udp的感觉就简单多了。

#region usings
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Threading;
#endregion

namespace NetStudy
{
    delegate void AppendItem(object o);
    public partial class MyTalkUdp : Form
    {
        #region Vars
        Thread serverThread;
        EndPoint  remoteIpep;
        Socket serverSock, clicentSock;

        AppendItem AddItem;
        void addItem(object o)
        {
            listBox.Items.Add(o);
        }
        string message;
        #endregion

        #region Constructions
        public MyTalkUdp()
        {
            InitializeComponent();
            AddItem = new AppendItem(addItem);
        }
        #endregion

        #region Events
        private void btSent_Click(object sender, EventArgs e)
        {
            IPAddress[] ipalist = Dns.GetHostAddresses(txtTarget.Text.Trim());
            if (ipalist.GetLength(0) <= 0)
            {
                listBox.Items.Add("Invalid Target!");
                return;
            }
            IPAddress ipa = ipalist[0];
            remoteIpep = new IPEndPoint(ipa, 8989);
            message = txtMessage.Text;
            txtMessage.Clear();
            SentMessage();
            listBox.Items.Add("TO " + remoteIpep.ToString() + ":" + message);
        }

        private void MyTalkUdp_Load(object sender, EventArgs e)
        {
            serverThread = new Thread(new ThreadStart(StartListen));
            serverThread.Start();
        }
        #endregion

        #region Methods
        void StartListen()
        {
            serverSock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            serverSock.Bind(new IPEndPoint(IPAddress.Any, 8989));
            byte[] buf=new byte[1024];
            IPEndPoint remotePoint=null;
            int bufLen = 0;
            bool isKeepAlive=true;
            string data;
            while (isKeepAlive)
            {
                try
                {
                    bufLen = serverSock.Available;
                    if (bufLen != 0)
                    {
                        serverSock.ReceiveFrom(buf, SocketFlags.None,ref remoteIpep);
                        data=System.Text.Encoding.Unicode.GetString(buf, 0, bufLen);
                        if (!string.IsNullOrEmpty(data))
                        {
                            listBox.Invoke(AddItem, "FROM " + remoteIpep.ToString() + ":" + data);
                        }
                    }
                }
                catch (SocketException sexc)
                {
                    listBox.Invoke(AddItem, sexc.Message);
                }
            }
            
        }
        void SentMessage()
        {
            if (string.IsNullOrEmpty(message)) return;
            byte[] buf=new byte[1024];
            buf = System.Text.Encoding.Unicode.GetBytes(message);
            clicentSock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            try
            {
                clicentSock.SendTo(buf, remoteIpep);
            }
            catch (SocketException sexc)
            {
                listBox.Items.Add(sexc.Message);
            }
        }
        #endregion
    }
}