利用晚上这点闲暇时间，写了一个Socket通信的小实例，该实例包含服务器端和客户端。其基本工作流程是：当服务器启动服务以后，客户端进行连接，如果连接成功，则用户可以在发送消息框中输入待发送的消息，然后点击“Send”按钮后向服务器发送消息，服务器在收到消息后立即向该客户端发送接收成功消息。其基本效果如图1.1和图1.2所示（注：下面两幅图于次日补上）：
图1.1 服务器运行效果图
图1.2 客户端运行效果图
现将服务器和客户端部分代码贴出来，由于代码较简单，基本没有注释，并在此特别说明，该实例仅仅是一个简单的示例，其中的代码仍有进一步修改优化空间，同时亦欢迎各位朋友批评指正。
服务器代码部分：
using System;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace SocketServer
{
public partial class frmServer : Form
{
private Thread m_serverThread;
private Socket m_serverSocket;
private string m_serverIP;
private int m_serverPort;
public delegate void ReceiveMessageDelegate(Client client);
ReceiveMessageDelegate receiveMessageDelegate;
public frmServer()
{
InitializeComponent();
Control.CheckForIllegalCrossThreadCalls = false;
}
private void frmServer_Load(object sender, EventArgs e)
{
string[] addresses = GetLocalAddresses();
cmbIP.Items.Clear();
if (addresses.Length > 0)
{
for (int i = 0; i < addresses.Length; i++)
{
cmbIP.Items.Add(addresses[i]);
}
cmbIP.Text = (string)cmbIP.Items[0];
}
txtPort.Text = "8899";
}
private void btnStart_Click(object sender, EventArgs e)
{
m_serverIP = cmbIP.Text;
m_serverPort = Int32.Parse(txtPort.Text);
Start();
btnStart.Enabled = false;
btnStop.Enabled = true;
}
private void btnStop_Click(object sender, EventArgs e)
{
Stop();
btnStart.Enabled = true;
btnStop.Enabled = false;
}
/// <summary>
/// 开始服务
/// </summary>
private void Start()
{
try
{
m_serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse(m_serverIP), m_serverPort);
m_serverSocket.Bind(localEndPoint);
m_serverSocket.Listen(10);
m_serverThread = new Thread(new ThreadStart(ReceiveAccept));
m_serverThread.Start();
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Server started.");
}
catch (SocketException se)
{
throw new Exception(se.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 停止服务
/// </summary>
private void Stop()
{
try
{
m_serverThread.Abort(); // 线程终止
m_serverSocket.Close(); // Socket Close
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Server stoped.");
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
private void ReceiveAccept()
{
while (true)
{
Client client = new Client();
try
{
client.ClientSocket = m_serverSocket.Accept();
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Client[" + client.ClientSocket.RemoteEndPoint.ToString() + "] connected.");
receiveMessageDelegate = new ReceiveMessageDelegate(ReceiveMessages);
receiveMessageDelegate.BeginInvoke(client, ReceiveMessagesCallback, "");
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
}
private void ReceiveMessages(Client client)
{
while (true)
{
byte[] receiveBuffer = new byte[1024];
client.ClientSocket.Receive(receiveBuffer);
string strReceiveData = Encoding.Unicode.GetString(receiveBuffer);
if (!string.IsNullOrEmpty(strReceiveData))
{
this.AddRunningInfo(">> Receive data from [" + client.ClientSocket.RemoteEndPoint.ToString()+ "]:" + strReceiveData);
string strSendData = "OK. The content is:" + strReceiveData;
int sendBufferSize = Encoding.Unicode.GetByteCount(strSendData);
byte[] sendBuffer = new byte[sendBufferSize];
sendBuffer = Encoding.Unicode.GetBytes(strSendData);
client.ClientSocket.Send(sendBuffer);
}
}
}
private void ReceiveMessagesCallback(IAsyncResult AR)
{
receiveMessageDelegate.EndInvoke(AR);
}
/// <summary>
/// 将运行信息加入显示列表
/// </summary>
private void AddRunningInfo(string message)
{
lstRunningInfo.BeginUpdate();
lstRunningInfo.Items.Insert(0, message);
if (lstRunningInfo.Items.Count > 100)
{
lstRunningInfo.Items.RemoveAt(100);
}
lstRunningInfo.EndUpdate();
}
/// <summary>
/// 获取本机地址列表
/// </summary>
public string[] GetLocalAddresses()
{
// 获取主机名
string strHostName = Dns.GetHostName();
// 根据主机名进行查找
IPHostEntry iphostentry = Dns.GetHostEntry(strHostName);
string[] retval = new string[iphostentry.AddressList.Length];
int i = 0;
foreach (IPAddress ipaddress in iphostentry.AddressList)
{
retval[i] = ipaddress.ToString();
i++;
}
return retval;
}
}
/// <summary>
/// 客户端会话信息类
/// </summary>
public class Client
{
Socket m_clientSocket;
public Client() { }
public Socket ClientSocket
{
get { return m_clientSocket; }
set { this.m_clientSocket = value; }
}
}
}
客户端部分：
using System;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
namespace SocketClient
{
public partial class frmClient : Form
{
private Socket m_clientSocket;
private byte[] m_receiveBuffer = new byte[1024];
public frmClient()
{
InitializeComponent();
Control.CheckForIllegalCrossThreadCalls = false;
}
private void frmClient_Load(object sender, EventArgs e)
{
txtIP.Text = "172.18.20.234";
txtPort.Text = "8899";
}
/// <summary>
/// 连接服务器
/// </summary>
private void btnConnect_Click(object sender, EventArgs e)
{
string serverIP = txtIP.Text;
int serverPort = Int32.Parse(txtPort.Text);
m_clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Parse(serverIP),serverPort);
try
{
m_clientSocket.Connect(remoteEndPoint);
if (m_clientSocket.Connected)
{
m_clientSocket.BeginReceive(m_receiveBuffer, 0, m_receiveBuffer.Length, 0, new AsyncCallback(ReceiveCallBack), null);
btnConnect.Enabled = false;
btnDisconnect.Enabled = true;
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Client connect server success.");
}
}
catch (Exception)
{
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Client connect server fail.");
m_clientSocket = null;
}
}
/// <summary>
/// 断开连接
/// </summary>
private void btnDisconnect_Click(object sender, EventArgs e)
{
if (m_clientSocket != null)
{
m_clientSocket.Close();
btnConnect.Enabled = true;
btnDisconnect.Enabled = false;
btnSend.Enabled = false;
this.AddRunningInfo(">> " + DateTime.Now.ToString() + " Client disconnected.");
}
}
/// <summary>
/// 发送信息
/// </summary>
private void btnSend_Click(object sender, EventArgs e)
{
string strSendData = txtSend.Text;
byte[] sendBuffer = new byte[1024];
sendBuffer = Encoding.Unicode.GetBytes(strSendData);
if (m_clientSocket != null)
{
m_clientSocket.Send(sendBuffer);
}
}
private void ReceiveCallBack(IAsyncResult ar)
{
try
{
int REnd = m_clientSocket.EndReceive(ar);
string strReceiveData = Encoding.Unicode.GetString(m_receiveBuffer, 0, REnd);
this.HandleMessage(strReceiveData);
m_clientSocket.BeginReceive(m_receiveBuffer, 0, m_receiveBuffer.Length, 0, new AsyncCallback(ReceiveCallBack), null);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 处理接收到的数据
/// </summary>
private void HandleMessage(string message)
{
message = message.Replace("/0", "");
if (!string.IsNullOrEmpty(message))
{
this.AddRunningInfo(">> Receive Data from server:" + message);
}
}
private void AddRunningInfo(string message)
{
lstRunningInfo.BeginUpdate();
lstRunningInfo.Items.Insert(0, message);
if (lstRunningInfo.Items.Count > 100)
{
lstRunningInfo.Items.RemoveAt(100);
}
lstRunningInfo.EndUpdate();
}
private void txtSend_TextChanged(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(txtSend.Text) && m_clientSocket!=null)
{
btnSend.Enabled = true;
}
else
{
btnSend.Enabled = false;
}
}
}
}