以下示例程序实现简单的Socket通信，可以开多个客户端。本机测试通过，未做联机测试。
Server：
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Collections;
namespace MySocketServer1
{
public partial class Form1 : Form
{
private IPAddress serverIP = IPAddress.Parse("127.0.0.1");//以本机作测试
private IPEndPoint serverFullAddr;//完整终端地址
private Socket sock;
private System.Timers.Timer myTimer;
private ArrayList alSock;//当建立了多个连接时用于保存连接
public Form1()
{
InitializeComponent();
}
private void btStart_Click(object sender, EventArgs e)
{
serverFullAddr = new IPEndPoint(serverIP, 1000);//取端口号1000
//构造Socket对象，套接字类型为“流套接字”，指定五元组中的协议元
sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream,
ProtocolType.Tcp);
//指定五元组中的本地二元，即本地主机地址和端口号
sock.Bind(serverFullAddr);
//监听是否有连接传入，指定挂起的连接队列的最大值为20
sock.Listen(20);
alSock = new ArrayList();
//构造定时器，时间间隙为1秒，即每隔一秒执行一次accept()方法，以获取连接请求队列中//第一个挂起的连接请求
myTimer =new System.Timers.Timer(1000);
myTimer.Elapsed +=new System.Timers.ElapsedEventHandler(myTimer_Elapsed);
myTimer.Enabled = true;
}
private void myTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
myTimer.Enabled = false;
//执行accept()，当挂起队列为空时将阻塞本线程，同时由于上一语句，定时器将停止，直//至有连接传入
Socket acceptSock = sock.Accept();
//将accept()产生的Socket对象存入ArrayList
alSock.Add(acceptSock);
// 构造Threading.Timer对象，这将导致程序另启线程。线程将执行回调函数，该委托限制//函数参数须为object型。Threading.Timer构造器的第二个参数即传入回调函数的参数；第//三个参数指定调用回调函数之前的延时，取0则立即启动；最后一个参数指定调用回调函数//的时间间隔，取0则只执行一次。
System.Threading.Timer ti = new System.Threading.Timer(new
TimerCallback(ReceiveMsg), acceptSock, 0, 0);
myTimer.Enabled = true;
}
private void ReceiveMsg(object obj)
{
Socket acceptSock = (Socket)obj;
try
{
while (true)
{
byte[] byteArray = new byte[100];
acceptSock.Receive(byteArray);//接收数据
//将字节数组转成字符串
string strRec = System.Text.Encoding.UTF8.GetString(byteArray);
if (this.rtbReceive.InvokeRequired)
{
this.rtbReceive.Invoke(new EventHandler(this.ChangeRickTextBox), new
object[] { strRec, EventArgs.Empty });
}
}
}
catch(Exception ex)
{
acceptSock.Close();
MessageBox.Show("S:Receive Message Error"+ex.Message);
}
}
private void ChangeRickTextBox(object obj,EventArgs e)
{
string s = System.Convert.ToString(obj);
this.rtbReceive.AppendText(s + Environment.NewLine);
}
private void btSend_Click(object sender, EventArgs e)
{
Socket sc=null;
byte[] byteSend =
System.Text.Encoding.UTF8.GetBytes(this.tbSend.Text.ToCharArray());
try
{
//同时存在若干个客户端连接时，在textBox1中输入要发送的是哪个连接
int index = int.Parse(this.textBox1.Text.Trim());
sc = (Socket)alSock[index - 1];
//发送数据
sc.Send(byteSend);
}
catch(Exception ex)
{
if(sc != null)
{
sc.Close();
}
MessageBox.Show("S:Send Message Error"+ex.Message);
}
}
private void btClose_Click(object sender, EventArgs e)
{
try
{
Application.Exit();
}
catch (Exception ex)
{
MessageBox.Show("S:Close Socket Error" + ex.Message);
}
}
}
}
== == == == == == == == == == == == == == == == == == == == == == == == == == == == == == == ==
Client:
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace MySocketClient1
{
public partial class Form1 : Form
{
private IPAddress serverIP = IPAddress.Parse("127.0.0.1");
private IPEndPoint serverFullAddr;
private Socket sock;
public Form1()
{
InitializeComponent();
}
private void btConnect_Click(object sender, EventArgs e)
{
try
{
serverFullAddr = new IPEndPoint(serverIP, 1000);
sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream,
ProtocolType.Tcp);
sock.Connect(serverFullAddr);//建立与远程主机的连接
//启动新线程用于接收数据
Thread t = new Thread(new ThreadStart(ReceiveMsg));
t.Name = "Receive Message";
//一个线程或者是后台线程或者是前台线程。后台线程与前台线程类似，区别是后台线//程不会防止进程终止。一旦属于某一进程的所有前台线程都终止，公共语言运行库就//会通过对任何仍然处于活动状态的后台线程调用 Abort 来结束该进程。
t.IsBackground = true;
t.Start();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void ReceiveMsg()
{
try
{
while (true)
{
byte[] byteRec = new byte[100];
this.sock.Receive(byteRec);
string strRec = System.Text.Encoding.UTF8.GetString(byteRec);
if (this.rtbReceive.InvokeRequired)
{
this.rtbReceive.Invoke(new EventHandler(ChangeRtb), new object[]
{ strRec, EventArgs.Empty });
}
}
}
catch(Exception ex)
{
MessageBox.Show("Receive Message Error"+ex.Message);
}
}
private void ChangeRtb(object obj, EventArgs e)
{
string s = System.Convert.ToString(obj);
this.rtbReceive.AppendText(s + Environment.NewLine);
}
private void btSend_Click(object sender, EventArgs e)
{
byte[] byteSend =
System.Text.Encoding.UTF8.GetBytes(this.tbSend.Text.ToCharArray());
try
{
this.sock.Send(byteSend);
}
catch
{
MessageBox.Show("Send Message Error");
}
}
private void btClose_Click(object sender, EventArgs e)
{
try
{
this.sock.Shutdown(SocketShutdown.Receive);
this.sock.Close();
Application.Exit();
}
catch
{
MessageBox.Show("Exit Error");
}
}
}
}
不解之处：
Client端红色标注语句：this.sock.Shutdown(SocketShutdown.Receive)，如改成
this.sock.Shutdown(SocketShutdown.Both);或this.sock.Shutdown(SocketShutdown.Send);
则当点击Cloce按钮时，CPU使用率疯涨到100%，而使用this.sock.Shutdown(SocketShutdown.Receive);
或不调用Shutdown()方法则没有这个问题。难道客户端不应该用Shutdown()？