Question

如何用C语言控制计算机串口

本人要用计算机控制串口的数据传输。跪求！！！ 本人采用VC6.0编译器
本人要求只要发送一个字节与接收一个字节就行了 是用于单片机的串口通信。
程序越简单越好 最好有现成的程序供参考 。。 小的不胜感激。。。。 在线等待。。

Answer 1

基本方法是使用CreateFile来建立一个串口文件，然后御咐用overlap的方式进行读写

#define SERAIL_PORT_BUF_MAX (1024*8)
typedef HRESULT (*PFN_CMD_PARSE_DATA)(HANDLE hParseApp, LPCSTR szRspCmd, int nCmdLen);

class CUsbSrvApp// : public CWinApp
{
public:
CUsbSrvApp();
~CUsbSrvApp();
BOOL OnSendData(const char *szBuf, int nLen);// 发送数据
int ComConnect(CString strPort); // 连接COM口
HANDLE OpenComPort(CString strPort, int nBaudRate, int nDataBits, int nStopBits, int nParity, int nFlowCtrlType); // 打开串口
void Close(); // 关闭串口

HANDLE m_hCom;
BOOL m_bConnected;
OVERLAPPED m_OverlappedRead;
OVERLAPPED m_OverlappedWrite;
CWinThread *m_pThread;

PFN_CMD_PARSE_DATA m_pRspCmdFunc; // 用来处理接受数据的CALLBACK
HANDLE m_hParseApp;
};

CUsbSrvApp::CUsbSrvApp()
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
m_bConnected = false;
m_hCom = NULL;
m_pRspCmdFunc = NULL;
}

CUsbSrvApp::~CUsbSrvApp()
{
}
//打开串口通信，并返回串口句柄
HANDLE CUsbSrvApp::OpenComPort(CString strPortName,
int nBaudRate,
int nDataBits,
int nStopBits,
int nParity,
int nFlowCtrlType)
{
DCB dcb;
COMMTIMEOUTS CommTimeOuts ;
COMMCONFIG ComConfig;
HANDLE hComPort;

CString strPort;
strPort.Format("\\\\.\\%s",strPortName); // COM口的文件名镇困纯应该是 \\.\COMXX

//打开窗口其实就是创建一个文件
hComPort = CreateFile(strPort,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED,
NULL);

if (INVALID_HANDLE_VALUE == hComPort)
return INVALID_HANDLE_VALUE;

//尺敬 设置一些COM口通讯参数和OVERLAP
CommTimeOuts.ReadIntervalTimeout = -1;
CommTimeOuts.ReadTotalTimeoutConstant = 0;
CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
CommTimeOuts.WriteTotalTimeoutConstant = 0;
CommTimeOuts.WriteTotalTimeoutMultiplier = 0x1388;
SetCommTimeouts( m_hCom, &CommTimeOuts ) ;

SetDefaultCommConfig(strPortName, &ComConfig, sizeof(COMMCONFIG));
GetCommState(m_hCom, &dcb ) ;

dcb.BaudRate = nBaudRate;
dcb.ByteSize = nDataBits;
dcb.StopBits = nStopBits;
dcb.fParity = (NOPARITY != nParity);
dcb.Parity = nParity;
//set the receive char
dcb.EvtChar = 0x0D;

switch(nFlowCtrlType)
{
case 0: //no flow control
break;

case 1://HARD_FLOW_CTRL:

dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = TRUE;
dcb.fRtsControl = RTS_CONTROL_TOGGLE;
break;

case 2://SOFT_FLOW_CTRL:
dcb.fOutX = TRUE;
dcb.fInX = TRUE;
break;
}
BuildCommDCB(_T("baud=115200 parity=N data=8 stop=1"),&dcb);
SetCommState(hComPort, &dcb ) ;
SetCommMask(hComPort, 0);
SetCommMask(hComPort, EV_RXCHAR|EV_CTS|EV_DSR|EV_RLSD|EV_RING);
SetupComm( hComPort, SERAIL_PORT_BUF_MAX,SERAIL_PORT_BUF_MAX) ;
//clear read and write buffer
PurgeComm( hComPort, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR );

return hComPort;
}

void CUsbSrvApp::Close()
{
if(m_bConnected)
{
m_bConnected = false;
CloseHandle(m_hCom);
m_hCom = NULL;
}
}

// 这个线程是监视串口数据，一旦有数据则读取并调用CALLBACK通知客户端
UINT ReceiveComData(LPVOID pParam)
{
CUsbSrvApp *pUsbSrv = (CUsbSrvApp *)pParam;
HANDLE hComPort = pUsbSrv->m_hCom;

DWORD dwEvtMask=0;
DWORD dwErrorFlags;

SetCommMask( hComPort, EV_RXCHAR);
OVERLAPPED osRead;
osRead.hEvent = CreateEvent(NULL,FALSE,FALSE,NULL);
DWORD dwTransfer = 0;
while(pUsbSrv->m_bConnected)
{
if( !WaitCommEvent( hComPort, &dwEvtMask,&osRead))
{
if( GetLastError()== ERROR_IO_PENDING)
{
WaitForSingleObject(osRead.hEvent, INFINITE);
if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
{
COMSTAT ComStat={0} ;
DWORD dwReadLen = 0;
DWORD dwBytesRead = 0;
DWORD dwTotalLen = 0;
ClearCommError(hComPort, &dwErrorFlags, &ComStat );
dwTotalLen = ComStat.cbInQue;
dwReadLen = (SERAIL_PORT_BUF_MAX > dwTotalLen)?dwTotalLen:SERAIL_PORT_BUF_MAX;

BYTE *pBuf = new BYTE[dwTotalLen+1];
memset(pBuf, 0 , dwTotalLen+1);
DWORD nReadBufLen=0;
while(dwTotalLen>0)
{

if(FALSE == ReadFile( hComPort, pBuf+nReadBufLen,dwReadLen, &dwBytesRead,&pUsbSrv->m_OverlappedRead))
{
if(GetLastError() == ERROR_IO_PENDING)
{
GetOverlappedResult(hComPort,&osRead, &dwTransfer, TRUE );
}
break;
}

nReadBufLen +=dwBytesRead;
dwTotalLen -=dwBytesRead;
dwReadLen -= dwBytesRead;
dwReadLen = (SERAIL_PORT_BUF_MAX>dwReadLen)?dwReadLen:SERAIL_PORT_BUF_MAX;
}
if(pUsbSrv->m_pRspCmdFunc!=NULL&&nReadBufLen!=0)
{
pUsbSrv->m_pRspCmdFunc(pUsbSrv->m_hParseApp, (char*)pBuf,nReadBufLen);
}

delete pBuf;

ClearCommError(hComPort, &dwErrorFlags, &ComStat );
int len =0;//= m_retList.GetSize();
}//endif if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
}//endif if( GetLastError()== ERROR_IO_PENDING)
}//endif if( !WaitCommEvent( hComPort, &dwEvtMask,&o))
else
{
if(GetLastError() == ERROR_IO_PENDING) {
GetOverlappedResult(hComPort, &osRead, &dwTransfer, TRUE ); // sleep thread
}
}
Sleep(1);
} //endwhile while(m_bConnected)
return 0;
}

int CUsbSrvApp::ComConnect(CString strPort)
{
int nBaudRate = 115200;
int nDataBits = 8;
int nStopBits = 1;
int nParity = 0;
int nFlowCtrl = 1;

if (NULL != m_hCom || m_bConnected)
{
return 0;
}
m_hCom = OpenComPort(strPort,nBaudRate,nDataBits,nStopBits,nParity,nFlowCtrl);
if( INVALID_HANDLE_VALUE == m_hCom)
{
m_hCom = NULL;
return 0;
}
memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );

m_pThread = AfxBeginThread( ReceiveComData,(void*)this,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED ,NULL );

if( NULL == m_pThread )
{
CloseHandle( m_hCom );
m_hCom = NULL;
return FALSE;
}
else
{
m_bConnected = TRUE;
m_pThread->ResumeThread( );
}

return TRUE;
}

int CUsbSrvApp::OnSendData(const char *szBuf, int nLen)
{
BOOL bWriteStat;
BOOL bWrite = TRUE;
DWORD dwBytesWrite = 0;
DWORD dwBytesWritten = 0;
int dwByteswrittenTotal = 0;

if (NULL == m_hCom)
return 0;

int nSentTimes=0;

while(dwByteswrittenTotal<nLen&&nSentTimes<10)
{
nSentTimes++;
dwBytesWrite = nLen-dwByteswrittenTotal;
bWriteStat = WriteFile( m_hCom, szBuf+dwByteswrittenTotal, dwBytesWrite, &dwBytesWritten, &m_OverlappedWrite );

if( !bWriteStat)
{
if ( GetLastError() == ERROR_IO_PENDING )
{
dwBytesWritten = 0;
bWrite = FALSE;
}
}
if (!bWrite)
{
bWrite = TRUE;

bWriteStat = GetOverlappedResult(m_hCom, // Handle to COMM port
&m_OverlappedWrite, // Overlapped structure
&dwBytesWritten, // Stores number of bytes sent
TRUE); // Wait flag
//deal with the error code
}
dwByteswrittenTotal += dwBytesWritten;
}
if(dwByteswrittenTotal<nLen)
return 0;
else
return 1;
}

Answer 2

基本方法是使用CreateFile来建立一个串口文件，然后用overlap的方式进行读写

#define SERAIL_PORT_BUF_MAX (1024*8)
typedef HRESULT (*PFN_CMD_PARSE_DATA)(HANDLE hParseApp, LPCSTR szRspCmd, int nCmdLen);

class CUsbSrvApp// : public CWinApp
{
public:
CUsbSrvApp();
~CUsbSrvApp();
BOOL OnSendData(const char *szBuf, int nLen);// 发送数据
int ComConnect(CString strPort); // 连接COM口
HANDLE OpenComPort(CString strPort, int nBaudRate, int nDataBits, int nStopBits, int nParity, int nFlowCtrlType); // 打开串口
void Close(); // 关闭串局逗铅口

HANDLE m_hCom;
BOOL m_bConnected;
OVERLAPPED m_OverlappedRead;
OVERLAPPED m_OverlappedWrite;
CWinThread *m_pThread;

PFN_CMD_PARSE_DATA m_pRspCmdFunc; // 用来处理接受数据桐好的CALLBACK
HANDLE m_hParseApp;
};

CUsbSrvApp::CUsbSrvApp()
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
m_bConnected = false;
m_hCom = NULL;
m_pRspCmdFunc = NULL;
}

CUsbSrvApp::~CUsbSrvApp()
{
}
//打开串口通信，并返回串口句柄
HANDLE CUsbSrvApp::OpenComPort(CString strPortName,
int nBaudRate,
int nDataBits,
int nStopBits,
int nParity,
int nFlowCtrlType)
{
DCB dcb;
COMMTIMEOUTS CommTimeOuts ;
COMMCONFIG ComConfig;
HANDLE hComPort;

CString strPort;
strPort.Format("\\\\.\\%s",strPortName); // COM口的文件名应该是 \\.\COMXX

//打开窗口其实就是指枝创建一个文件
hComPort = CreateFile(strPort,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED,
NULL);

if (INVALID_HANDLE_VALUE == hComPort)
return INVALID_HANDLE_VALUE;

// 设置一些COM口通讯参数和OVERLAP
CommTimeOuts.ReadIntervalTimeout = -1;
CommTimeOuts.ReadTotalTimeoutConstant = 0;
CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
CommTimeOuts.WriteTotalTimeoutConstant = 0;
CommTimeOuts.WriteTotalTimeoutMultiplier = 0x1388;
SetCommTimeouts( m_hCom, &CommTimeOuts ) ;

SetDefaultCommConfig(strPortName, &ComConfig, sizeof(COMMCONFIG));
GetCommState(m_hCom, &dcb ) ;

dcb.BaudRate = nBaudRate;
dcb.ByteSize = nDataBits;
dcb.StopBits = nStopBits;
dcb.fParity = (NOPARITY != nParity);
dcb.Parity = nParity;
//set the receive char
dcb.EvtChar = 0x0D;

switch(nFlowCtrlType)
{
case 0: //no flow control
break;

case 1://HARD_FLOW_CTRL:

dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = TRUE;
dcb.fRtsControl = RTS_CONTROL_TOGGLE;
break;

case 2://SOFT_FLOW_CTRL:
dcb.fOutX = TRUE;
dcb.fInX = TRUE;
break;
}
BuildCommDCB(_T("baud=115200 parity=N data=8 stop=1"),&dcb);
SetCommState(hComPort, &dcb ) ;
SetCommMask(hComPort, 0);
SetCommMask(hComPort, EV_RXCHAR|EV_CTS|EV_DSR|EV_RLSD|EV_RING);
SetupComm( hComPort, SERAIL_PORT_BUF_MAX,SERAIL_PORT_BUF_MAX) ;
//clear read and write buffer
PurgeComm( hComPort, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR );

return hComPort;
}

void CUsbSrvApp::Close()
{
if(m_bConnected)
{
m_bConnected = false;
CloseHandle(m_hCom);
m_hCom = NULL;
}
}

// 这个线程是监视串口数据，一旦有数据则读取并调用CALLBACK通知客户端
UINT ReceiveComData(LPVOID pParam)
{
CUsbSrvApp *pUsbSrv = (CUsbSrvApp *)pParam;
HANDLE hComPort = pUsbSrv->m_hCom;

DWORD dwEvtMask=0;
DWORD dwErrorFlags;

SetCommMask( hComPort, EV_RXCHAR);
OVERLAPPED osRead;
osRead.hEvent = CreateEvent(NULL,FALSE,FALSE,NULL);
DWORD dwTransfer = 0;
while(pUsbSrv->m_bConnected)
{
if( !WaitCommEvent( hComPort, &dwEvtMask,&osRead))
{
if( GetLastError()== ERROR_IO_PENDING)
{
WaitForSingleObject(osRead.hEvent, INFINITE);
if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
{
COMSTAT ComStat={0} ;
DWORD dwReadLen = 0;
DWORD dwBytesRead = 0;
DWORD dwTotalLen = 0;
ClearCommError(hComPort, &dwErrorFlags, &ComStat );
dwTotalLen = ComStat.cbInQue;
dwReadLen = (SERAIL_PORT_BUF_MAX > dwTotalLen)?dwTotalLen:SERAIL_PORT_BUF_MAX;

BYTE *pBuf = new BYTE[dwTotalLen+1];
memset(pBuf, 0 , dwTotalLen+1);
DWORD nReadBufLen=0;
while(dwTotalLen>0)
{

if(FALSE == ReadFile( hComPort, pBuf+nReadBufLen,dwReadLen, &dwBytesRead,&pUsbSrv->m_OverlappedRead))
{
if(GetLastError() == ERROR_IO_PENDING)
{
GetOverlappedResult(hComPort,&osRead, &dwTransfer, TRUE );
}
break;
}

nReadBufLen +=dwBytesRead;
dwTotalLen -=dwBytesRead;
dwReadLen -= dwBytesRead;
dwReadLen = (SERAIL_PORT_BUF_MAX>dwReadLen)?dwReadLen:SERAIL_PORT_BUF_MAX;
}
if(pUsbSrv->m_pRspCmdFunc!=NULL&&nReadBufLen!=0)
{
pUsbSrv->m_pRspCmdFunc(pUsbSrv->m_hParseApp, (char*)pBuf,nReadBufLen);
}

delete pBuf;

ClearCommError(hComPort, &dwErrorFlags, &ComStat );
int len =0;//= m_retList.GetSize();
}//endif if(dwEvtMask&EV_RXCHAR==EV_RXCHAR)
}//endif if( GetLastError()== ERROR_IO_PENDING)
}//endif if( !WaitCommEvent( hComPort, &dwEvtMask,&o))
else
{
if(GetLastError() == ERROR_IO_PENDING) {
GetOverlappedResult(hComPort, &osRead, &dwTransfer, TRUE ); // sleep thread
}
}
Sleep(1);
} //endwhile while(m_bConnected)
return 0;
}

int CUsbSrvApp::ComConnect(CString strPort)
{
int nBaudRate = 115200;
int nDataBits = 8;
int nStopBits = 1;
int nParity = 0;
int nFlowCtrl = 1;

if (NULL != m_hCom || m_bConnected)
{
return 0;
}
m_hCom = OpenComPort(strPort,nBaudRate,nDataBits,nStopBits,nParity,nFlowCtrl);
if( INVALID_HANDLE_VALUE == m_hCom)
{
m_hCom = NULL;
return 0;
}
memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );

m_pThread = AfxBeginThread( ReceiveComData,(void*)this,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED ,NULL );

if( NULL == m_pThread )
{
CloseHandle( m_hCom );
m_hCom = NULL;
return FALSE;
}
else
{
m_bConnected = TRUE;
m_pThread->ResumeThread( );
}

return TRUE;
}

int CUsbSrvApp::OnSendData(const char *szBuf, int nLen)
{
BOOL bWriteStat;
BOOL bWrite = TRUE;
DWORD dwBytesWrite = 0;
DWORD dwBytesWritten = 0;
int dwByteswrittenTotal = 0;

if (NULL == m_hCom)
return 0;

int nSentTimes=0;

while(dwByteswrittenTotal<nLen&&nSentTimes<10)
{
nSentTimes++;
dwBytesWrite = nLen-dwByteswrittenTotal;
bWriteStat = WriteFile( m_hCom, szBuf+dwByteswrittenTotal, dwBytesWrite, &dwBytesWritten, &m_OverlappedWrite );

if( !bWriteStat)
{
if ( GetLastError() == ERROR_IO_PENDING )
{
dwBytesWritten = 0;
bWrite = FALSE;
}
}
if (!bWrite)
{
bWrite = TRUE;

bWriteStat = GetOverlappedResult(m_hCom, // Handle to COMM port
&m_OverlappedWrite, // Overlapped structure
&dwBytesWritten, // Stores number of bytes sent
TRUE); // Wait flag
//deal with the error code
}
dwByteswrittenTotal += dwBytesWritten;
}
if(dwByteswrittenTotal<nLen)
return 0;
else
return 1;
}

Answer 3

打开VC++6.0，新建基于对话框的工程RS485Comm，在主对话框窗口IDD_RS485COMM_DIALOG上添加两个按钮，ID分别为IDC_SEND和IDC_RECEIVE，标题分别为“发送”和“接收”；添加一个静态文本框IDC_DISP，用于显示串口接收到的内容。 在RS485CommDlg.cpp文件中添加全局变量：差物扒 HANDLE hCom; //全局变量，串口句柄 在RS485CommDlg.cpp文件中的OnInitDialog()函数添加如下代码： // TODO: Add extra initialization here 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 0, //同步方式 NULL); if(hCom==(HANDLE)-1) { AfxMessageBox("打开COM失败!"); return FALSE; } SetupComm(hCom,100,100); //输入蚂仔缓冲区和输出缓冲区的大小都是1024 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=9600; //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); 分别双击IDC_SEND按钮和IDC_RECEIVE按钮，添加两个按钮的响应函数： void CRS485CommDlg::OnSend() { // TODO: Add your control notification handler code here // 在此需要简单介绍百特公司XMA5000的通讯协议： //该仪表RS485通讯采用主机广播方式通讯。 //串行半双工，帧11位，1个起始位(0)，8个数据位，2个停止位(1) //如：读仪表显示的瞬时值，主机发送：DC1 AAA BB ETX //其中：DC1是标准ASCII码的一个控制符号，码值为11H(十进制的17) //在XMA5000的通讯协议中，DC1表示读瞬时值 //AAA是从机地址码，也就是XMA5000显示仪表的通讯地址 //BB为通道号，读瞬时值时该值为01 //ETX也是标准ASCII码的一个控制符号，码值为03H //在XMA5000的通讯协议中，ETX表示主机结束符 char lpOutBuffer[7]; memset(lpOutBuffer,''\0'',7); //前7个字节先清零 lpOutBuffer[0]=''虚昌\x11''; //发送缓冲区的第1个字节为DC1 lpOutBuffer[1]=''0''; //第2个字节为字符0(30H) lpOutBuffer[2]=''0''; //第3个字节为字符0(30H) lpOutBuffer[3]=''1''; // 第4个字节为字符1(31H) lpOutBuffer[4]=''0''; //第5个字节为字符0(30H) lpOutBuffer[5]=''1''; //第6个字节为字符1(31H) lpOutBuffer[6]=''\x03''; //第7个字节为字符ETX //从该段代码可以看出，仪表的通讯地址为001 DWORD dwBytesWrite=7; COMSTAT ComStat; DWORD dwErrorFlags; BOOL bWriteStat; ClearCommError(hCom,&dwErrorFlags,&ComStat); bWriteStat=WriteFile(hCom,lpOutBuffer,dwBytesWrite,& dwBytesWrite,NULL); if(!bWriteStat) { AfxMessageBox("写串口失败!"); } } void CRS485CommDlg::OnReceive() { // TODO: Add your control notification handler code here char str[100]; memset(str,''\0'',100); DWORD wCount=100;//读取的字节数 BOOL bReadStat; bReadStat=ReadFile(hCom,str,wCount,&wCount,NULL); if(!bReadStat) AfxMessageBox("读串口失败!"); PurgeComm(hCom, PURGE_TXABORT| PURGE_RXABORT|PURGE_TXCLEAR|PURGE_RXCLEAR); m_disp=str; UpdateData(FALSE); } 您可以观察返回的字符串，其中有和仪表显示值相同的部分，您可以进行相应的字符串操作取出仪表的显示值。 打开ClassWizard,为静态文本框IDC_DISP添加CString类型变量m_disp，同时添加WM_CLOSE的相应函数： void CRS485CommDlg::OnClose() { // TODO: Add your message handler code here and/or call default CloseHandle(hCom); //程序退出时关闭串口 CDialog::OnClose(); } 程序的相应部分已经在代码内部作了详细介绍。连接好硬件部分，编译运行程序，细心体会串口同步操作部分。