本人用vs編了一個mscomm串口通信程式，正常的收發都可以，接收文本的編輯框關聯了CString變數，我現在要求實作mscomm1.setoutput()發送一條指令后，下位機自動會回復一條資訊（下位機自己發的），接收到資料并改變CString變數然后才能處理，現在編輯框能收到回復的指令，但是CString的值卻不會變化。。。。
另外，我發送完一條mscomm1.setoutput()，下位機會自動回復一條資訊，此時是直接進入OnCommMscomm1()接識訓呼函式嗎？求指教。。。。。。
uj5u.com熱心網友回復：
你可以在OnCommMscomm1()設定斷點，看回傳的是什么值呀uj5u.com熱心網友回復：
void CUseMsComm32OCXDlg::OnMscomm()
{
// TODO: Add your control notification handler code here
CString strEvent, strError;
CString str;
short evt=m_MyMSComm.GetCommEvent();
switch(evt)
{ //Events
case ComEvSend: // There are SThreshold number of characters in the transmit buffer.
strEvent="Sending";
break;
case ComEvReceive: // Received RThreshold number of chars.
{
// strEvent="Receiving";
VARIANT var;
var=m_MyMSComm.GetInput();
//
if(m_MyMSComm.GetInputMode()==ComInputModeText)
{// ComInputModeText
str=var.bstrVal;
}
else
{// ComInputModeBinary, although Text !
COleSafeArray arr;
arr=var;
long len=arr.GetOneDimSize();
BYTE Data[4096];
Data[len]=0;// sz
for(long jj=0;jj < len;jj++)
{
arr.GetElement(&jj, &Data[jj]);
}
// if true binary, we should convert the Data to string
char *newStr=0;
newStr=(char*)KillHalfHZ(Data,len);// no sz !
str=Data;
}
ShowData(str);
break;
}
case ComEvCTS: // Change in the CTS line.
// strEvent="CTS changed";
break;
case ComEvDSR: // Change in the DSR line.
strEvent="DSR changed";
break;
case ComEvCD: // Change in the CD line.
// strEvent="CDC changed";
break;
case ComEvRing: // Change in the Ring Indicator.
strEvent="Phone Ring";
break;
case ComEvEOF: // An EOF charater was found in the input stream
strEvent="EOF detected";
break;
// Errors
case ComEventBreak: // A Break was received.
strError="Break Received";
break;
case 1002: // vbMSCommErCTSTO:
strError="CTS Timeout";
break;
case 1003: // vbMSCommErDSRTO:
strError="DSR Timeout";
break;
case ComEventFrame: // Framing Error
strError="Framing Error";
break;
case ComEventOverrun: // Data Lost.
strError="Overrun Error";
break;
case 1007: // vbMSCommErCDTO:
strError="CD TimeOut";
break;
case ComEventRxOver: // Receive buffer overflow.
strError="R buffer Overflow";
break;
case ComEventRxParity: // Parity Error.
strError="Parity Error";
break;
case ComEventTxFull: // Transmit buffer full.
strError="T buf Full";
break;
case ComEventDCB: // Unexpected error retrieving DCB
strError="DCB error";
break;
}
//
if (!strEvent.IsEmpty())
{
AfxMessageBox(strEvent);
}
if (!strError.IsEmpty())
{
AfxMessageBox("ComError", MB_ICONEXCLAMATION);
m_MyMSComm.SetPortOpen(FALSE);
}
}
.cpp
BEGIN_EVENTSINK_MAP(CUseMsComm32OCXDlg, CDialog)
//{{AFX_EVENTSINK_MAP(CUseMsComm32OCXDlg)
ON_EVENT(CUseMsComm32OCXDlg, IDC_MSCOMM1, 1 /* OnComm */, OnMscomm, VTS_NONE)
//}}AFX_EVENTSINK_MAP
END_EVENTSINK_MAP()
.h
afx_msg void OnMscomm();
void CUseMsComm32OCXDlg::ShowData(LPCTSTR pchData)
{
CString str;
int nCharIndex;
int nBackcount = 0;
// Make sure existing text doesn't get too large.
int len = m_Edit.GetWindowTextLength();
if (len >= 16384)
{
m_Edit.GetWindowText(str);
m_Edit.SetWindowText(str.GetBuffer(len)+4097);
len -= 4097;
}
// Handle backspace characters.
str = pchData;
while ((nCharIndex = str.Find(TCHAR(VK_BACK))) != -1)
{
if (nCharIndex == 0)
{
nBackcount++;
str = str.Mid(nCharIndex+1);
}
else
{
str = str.Left(nCharIndex-1) + str.Mid(nCharIndex+1);
}
}
// Set text insertion point according to number of backspaces
// at the begining of strData.
if (nBackcount>len) nBackcount = len;
m_Edit.SetSel(len-nBackcount,len);
// Eliminate line feeds.
while ((nCharIndex = str.Find(TCHAR('\n'))) != -1)
{// delete all 0Ah
str = str.Left(nCharIndex) + str.Mid(nCharIndex + 1);
}
// Ensure all carriage returns have a line feed following.
LPCTSTR pchStart = (LPCTSTR)str;
LPTSTR pchIndex = _tcschr(pchStart,(TCHAR)'\r');
while (pchIndex != NULL)
{// add
int nPos = pchIndex - pchStart;
str = str.Left(nPos+1) + CString('\n') + str.Mid(nPos+1);
// Above operation probably allocated a new string buffer.
pchStart = (LPCTSTR)str;
pchIndex = _tcschr(pchStart + nPos + 1,(TCHAR)'\r');
}
// Add filtered data to edit control.
m_Edit.ReplaceSel(str);
}
uj5u.com熱心網友回復：
https://wenku.baidu.com/view/4de60424dd36a32d7375815a.htmluj5u.com熱心網友回復：
這個要看你通訊設定了，默認的好像是系統只要接收到一個字符就會進回呼。但是這樣同時會帶來另外一個問題，就是當對方發送資料稍微長一點時，你這邊可能會分批接收。uj5u.com熱心網友回復：
參考《編譯原理》中的詞法分析和有限狀態自動機。uj5u.com熱心網友回復：
謝謝大家 已經解決了轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/65448.html
標籤：基礎類