rs485_2dlg.cpp

一个串口通讯的例子,适合初学者,欢迎大家提宝贵意见!

// rs485_2Dlg.cpp : 实现文件
//

#include "stdafx.h"
#include "rs485_2.h"
#include "rs485_2Dlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// 用于应用程序“关于”菜单项的 CAboutDlg 对话框

class CAboutDlg : public CDialog
{
public:
	CAboutDlg();

// 对话框数据
	enum { IDD = IDD_ABOUTBOX };

	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV 支持

// 实现
protected:
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
END_MESSAGE_MAP()


// Crs485_2Dlg 对话框



Crs485_2Dlg::Crs485_2Dlg(CWnd* pParent /*=NULL*/)
	: CDialog(Crs485_2Dlg::IDD, pParent)
	, m_disp(_T(""))
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void Crs485_2Dlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	DDX_Text(pDX, IDC_EDIT1, m_disp);
}

BEGIN_MESSAGE_MAP(Crs485_2Dlg, CDialog)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	//}}AFX_MSG_MAP
	ON_BN_CLICKED(IDC_send, OnBnClickedsend)
	ON_BN_CLICKED(IDC_receive, OnBnClickedreceive)
	ON_BN_CLICKED(IDCANCEL, OnBnClickedCancel)
	ON_WM_CLOSE()
END_MESSAGE_MAP()


// Crs485_2Dlg 消息处理程序

BOOL Crs485_2Dlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// 将\“关于...\”菜单项添加到系统菜单中。

	// IDM_ABOUTBOX 必须在系统命令范围内。
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		CString strAboutMenu;
		strAboutMenu.LoadString(IDS_ABOUTBOX);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
	//  执行此操作
	SetIcon(m_hIcon, TRUE);			// 设置大图标
	SetIcon(m_hIcon, FALSE);		// 设置小图标

	// TODO：在此添加额外的初始化代码
	hCom=CreateFile("COM1",//COM1口
		GENERIC_READ|GENERIC_WRITE, //允许读和写
		0, //独占方式
		NULL,
		OPEN_EXISTING, //打开而不是创建
		FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED, //重叠方式
		NULL);
	if(hCom==(HANDLE)-1)
	{
		AfxMessageBox("打开COM失败!");
		return FALSE;
	}

	SetupComm(hCom,100,100); //输入缓冲区和输出缓冲区的大小都是100

	COMMTIMEOUTS TimeOuts;
	//设定读超时
	TimeOuts.ReadIntervalTimeout=MAXDWORD;
	TimeOuts.ReadTotalTimeoutMultiplier=0;
	TimeOuts.ReadTotalTimeoutConstant=0;
	//在读一次输入缓冲区的内容后读操作就立即返回，
	//而不管是否读入了要求的字符。


	//设定写超时
	TimeOuts.WriteTotalTimeoutMultiplier=100;
	TimeOuts.WriteTotalTimeoutConstant=500;
	SetCommTimeouts(hCom,&TimeOuts); //设置超时

	DCB dcb;
	GetCommState(hCom,&dcb);
	dcb.BaudRate=19200; //波特率为9600
	dcb.ByteSize=8; //每个字节有8位
	dcb.Parity=NOPARITY; //无奇偶校验位
	dcb.StopBits=TWOSTOPBITS; //两个停止位
	SetCommState(hCom,&dcb);

	PurgeComm(hCom,PURGE_TXCLEAR|PURGE_RXCLEAR);

	return TRUE;  // 除非设置了控件的焦点，否则返回 TRUE
}

void Crs485_2Dlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialog::OnSysCommand(nID, lParam);
	}
}

// 如果向对话框添加最小化按钮，则需要下面的代码
//  来绘制该图标。对于使用文档/视图模型的 MFC 应用程序，
//  这将由框架自动完成。

void Crs485_2Dlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // 用于绘制的设备上下文

		SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

		// 使图标在工作矩形中居中
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// 绘制图标
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

//当用户拖动最小化窗口时系统调用此函数取得光标显示。
HCURSOR Crs485_2Dlg::OnQueryDragIcon()
{
	return static_cast<HCURSOR>(m_hIcon);
}

void Crs485_2Dlg::OnBnClickedsend()
{
	// TODO: 在此添加控件通知处理程序代码
	OVERLAPPED m_osWrite;
	memset(&m_osWrite,0,sizeof(OVERLAPPED));
	m_osWrite.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);


	char lpOutBuffer[7];
	memset(lpOutBuffer,'\0',7);
	lpOutBuffer[0]='\x11';
	lpOutBuffer[1]='0';
	lpOutBuffer[2]='0';
	lpOutBuffer[3]='1';
	lpOutBuffer[4]='0';
	lpOutBuffer[5]='1';
	lpOutBuffer[6]='\x03';
	
	DWORD dwBytesWrite=7;
	COMSTAT ComStat;
	DWORD dwErrorFlags;
	BOOL bWriteStat;
	ClearCommError(hCom,&dwErrorFlags,&ComStat);
	bWriteStat=WriteFile(hCom,lpOutBuffer,
		dwBytesWrite,& dwBytesWrite,&m_osWrite);

	if(!bWriteStat)
	{
		if(GetLastError()==ERROR_IO_PENDING)
		{
			WaitForSingleObject(m_osWrite.hEvent,1000);
		}
	}

}

void Crs485_2Dlg::OnBnClickedreceive()
{
	// TODO: 在此添加控件通知处理程序代码
	OVERLAPPED m_osRead;
	memset(&m_osRead,0,sizeof(OVERLAPPED));
	m_osRead.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);

	COMSTAT ComStat;
	DWORD dwErrorFlags;
	
	char str[100];
	memset(str,'\0',100);
	DWORD dwBytesRead=100;//读取的字节数
	BOOL bReadStat;

	ClearCommError(hCom,&dwErrorFlags,&ComStat);
	dwBytesRead=min(dwBytesRead, (DWORD)ComStat.cbInQue);
	bReadStat=ReadFile(hCom,str,
		dwBytesRead,&dwBytesRead,&m_osRead);
	if(!bReadStat)
	{
		if(GetLastError()==ERROR_IO_PENDING)
	    //GetLastError()函数返回ERROR_IO_PENDING,表明串口正在进行读操作
		{
			WaitForSingleObject(m_osRead.hEvent,2000);
		    //使用WaitForSingleObject函数等待，直到读操作完成或延时已达到2秒钟
		    //当串口读操作进行完毕后，m_osRead的hEvent事件会变为有信号
		}
	}

	PurgeComm(hCom, PURGE_TXABORT|
		PURGE_RXABORT|PURGE_TXCLEAR|PURGE_RXCLEAR);
	m_disp=str;
	UpdateData(FALSE);

}

void Crs485_2Dlg::OnBnClickedCancel()
{
	// TODO: 在此添加控件通知处理程序代码
	
	OnCancel();
}

void Crs485_2Dlg::OnClose()
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	CloseHandle(hCom);
	CDialog::OnClose();
}