C#：一个增强的TcpListener（二）线程池

using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Threading;

namespace Splash.Net.Sockets
{
public partial class TcpListenerPlus : TcpListener
{
/// <summary>
/// 委托声明
/// </summary>
/// <param name="sender">事件发送者</param>
/// <param name="e">事件参数</param>
public delegate void ThreadTaskRequest(object sender, EventArgs e);

/// <summary>
/// 线程任务请求事件
/// </summary>
public event ThreadTaskRequest OnThreadTaskRequest;

// 已接受的Tcp连接列表
protected List<TcpClient> _tcpClients;

/// <summary>
/// 连接列表操作互斥量
/// </summary>
private Mutex _mutexClients;

/// <summary>
/// 侦听连接线程
/// </summary>
private void ListenThreadAction()
{   // 启动侦听
Start();

// 初始化连接列表和互斥量
_tcpClients = new List<TcpClient>();
_mutexClients = new Mutex();

// 接受连接
while (true)
{
TcpClient tcpClient = null;
try
{   // 接受挂起的连接请求
tcpClient = AcceptTcpClient();

// 将该连接通信加入线程池队列
ThreadPool.QueueUserWorkItem(ThreadPoolCallback, tcpClient);

// 连接加入列表
_mutexClients.WaitOne();
_tcpClients.Add(tcpClient);
_mutexClients.ReleaseMutex();
}

catch (SocketException)
{   // 结束侦听线程
break;
}

catch (Exception)
{   // 加入队列失败
if (tcpClient != null)
{
tcpClient.Close();
}
}
}
}

/// <summary>
/// 线程池回调方法
/// </summary>
/// <param name="state">回调方法要使用的信息对象</param>
private void ThreadPoolCallback(Object state)
{   // 如果无法进行转换，则 as 返回 null 而非引发异常
TcpClient tcpClient = state as TcpClient;
try
{   // 执行任务
if (OnThreadTaskRequest != null)
{
OnThreadTaskRequest(tcpClient, EventArgs.Empty);
}
}

catch
{
// 阻止异常抛出
}

finally
{   // 关闭连接
tcpClient.Close();

// 从列表中移除连接
_mutexClients.WaitOne();
if (_tcpClients != null)
{
_tcpClients.Remove(tcpClient);
}
_mutexClients.ReleaseMutex();
}
}

/// <summary>
/// 关闭侦听器
/// </summary>
/// <remarks>显示隐藏从基类继承的成员</remarks>
public new void Stop()
{   // 检测是否已开启侦听
if (Active)
{
// 关闭侦听器
base.Stop();

// 关闭已建立的连接
_mutexClients.WaitOne();
if (_tcpClients != null)
{
foreach (TcpClient client in _tcpClients)
{
client.Close();
}

// 清空连接列表
_tcpClients.Clear();
_tcpClients = null;
}
_mutexClients.ReleaseMutex();
}
}
}
}