服务器端
TCPServer
1、使用的通讯通道：socket
2、用到的基本功能：
Bind,
Listen,
BeginAccept
EndAccept
BeginReceive
EndReceive
3、函数参数说明
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
新建socket所使用的参数均为系统预定义的量，直接选取使用。
listener.Bind(localEndPoint);
localEndPoint 表示一个定义完整的终端，包括IP和端口信息。
//new IPEndPoint(IPAddress,port)
//IPAdress.Parse("192.168.1.3")
listener.Listen(100);
监听
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
AsyncCallback(AcceptCallback),一旦连接上后的回调函数为AcceptCallback。当系统调用这个函数时，自动赋予的输入参数为IAsyncResoult类型变量ar。
listener，连接行为的容器。
Socket handler = listener.EndAccept(ar);
完成连接，返回此时的socket通道。
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
接收的字节，0，字节长度，0，接收时调用的回调函数，接收行为的容器。
========
容器的结构类型为：
public class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
容器至少为一个socket类型。
===============
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
完成一次连接。数据存储在state.buffer里，bytesRead为读取的长度。
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
发送数据byteData，回调函数SendCallback。容器handler
int bytesSent = handler.EndSend(ar);
发送完毕，bytesSent发送字节数。
4 程序结构
主程序：
byte[] bytes = new Byte[1024];
IPAddress ipAddress = IPAddress.Parse("192.168.1.104");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
// 生成一个TCP的socket
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
//开启异步监听socket
Console.WriteLine("Waiting for a connection");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// 让程序等待，直到连接任务完成。在AcceptCallback里的适当位置放置allDone.Set()语句.
allDone.WaitOne();
}
Console.WriteLine("\nPress ENTER to continue");
Console.Read();
连接行为回调函数AcceptCallback：
public static void AcceptCallback(IAsyncResult ar)
{
//添加此命令，让主线程继续.
allDone.Set();
// 获取客户请求的socket
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// 造一个容器，并用于接收命令.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
读取行为的回调函数ReadCallback:
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
// 从异步state对象中获取state和socket对象.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// 从客户socket读取数据.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// 如果接收到数据，则存起来
state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
// 检查是否有结束标记，如果没有则继续读取
content = state.sb.ToString();
if (content.IndexOf("") > -1)
{
//所有数据读取完毕.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
// 给客户端响应.
Send(handler, content);
}
else
{
// 接收未完成，继续接收.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
发送消息给客户端：
private static void Send(Socket handler, String data)
{
// 消息格式转换.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// 开始发送数据给远程目标.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar)
{
// 从state对象获取socket.
Socket handler = (Socket)ar.AsyncState;
//完成数据发送
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
}
在各种行为的回调函数中，所对应的socket都从输入参数的AsyncState属性获得。使用（Socket）或者（StateObject）进行强制转换。BeginReceive函数使用的容器为state，因为它需要存放传送的数据。
而其余接收或发送函数的容器为socket也可。
完整代码
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
// State object for reading client data asynchronously
public class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousSocketListener
{
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public AsynchronousSocketListener()
{
}
public static void StartListening()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// The DNS name of the computer
// running the listener is "host.contoso.com".
//IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = IPAddress.Parse("192.168.1.104");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Console.WriteLine("Waiting for a connection");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nPress ENTER to continue");
Console.Read();
}
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
if (content.IndexOf("") > -1)
{
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
// Echo the data back to the client.
Send(handler, content);
}
else
{
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public static int Main(String[] args)
{
StartListening();
return 0;
}
}
