延迟一段时间调用SendMessage发送Windows消息

#pragma once

#include <boost/thread.hpp>
#include <boost/asio.hpp>

#include <functional>

/*
功能：延迟一段时间调用SendMessage发送Windows消息
测试环境：
[1]VS2013 Sp3
[2]boost 1.56
使用方式：
Step1:把CDelayEvent属性化为当前类成员。
Step2:在任意地方调用，例子如下
m_delayEvent.SendMessage(::SendMessage, GetSafeHwnd(), WM_MYUPDATEVIEW, 0, 0, 0);
可重复调用。
N次调用，会有N个事件等待执行。
Step3:
然后延迟一段时间后，SendMessage函数就会被调用。
*/

namespace kagula
{
	typedef std::function<long (const HWND hwnd, const UINT msg, 
		const WPARAM wParam, const LPARAM lParam)> Callback;  
	
	class CDelayEvent
	{
	public:
		CDelayEvent();
		~CDelayEvent();

		void SendMessage(Callback callback, const HWND hwnd, const UINT msg,
			const WPARAM wParam=0, const LPARAM lParam=0, int millisecond=1000/30);
	private:	
		boost::asio::io_service _service;
		/*
		    if no _work object, after all thing done, the _service.run will continue
		then thread will end.
		*/
		boost::asio::io_service::work _work;
		boost::asio::deadline_timer _deadlineTimer;
		
		boost::thread _thread;
	};
}

#include "stdafx.h"
#include "DelayEvent.h"

#include <boost/bind.hpp>

namespace kagula
{
	CDelayEvent::CDelayEvent() :_work(_service), _deadlineTimer(_service)
	{
		boost::thread t(boost::bind(&boost::asio::io_service::run, &_service));
		_thread = boost::move(t);
	}
	
	
	CDelayEvent::~CDelayEvent()
	{
		_service.stop();
		_thread.join();
	}

	void CDelayEvent::SendMessage(Callback callback, const HWND hwnd, 
		const UINT msg, const WPARAM wParam, const LPARAM lParam, int millisecond)
	{
		_deadlineTimer.expires_from_now(boost::posix_time::milliseconds(millisecond));
		_deadlineTimer.async_wait(boost::bind(callback, hwnd, msg, wParam, lParam));
	}
}