VS2010 MFC windows API 串口编程（一）

VS2010 MFC windows API 串口编程 （一）

部分来自：
http://www.cnblogs.com/jxnclyk/archive/2010/06/07/1753226.html

多数涉及串口操作的软件，在让用户选择串口时，只会机械的给出从COM1到COM16的组合框。但实际上可能有大于COM16的串口号，于是想编程来获取实际的串口号再列出来。看起来很难，其实关于串口的信息保存了注册表中，

void CPageSetCom::ShowComm()
{
long  lReg; 
HKEY  hKey; 
DWORD  MaxValueLength; 
DWORD  dwValueNumber; 

lReg=RegOpenKeyExA(HKEY_LOCAL_MACHINE, "HARDWARE\\DEVICEMAP\\SERIALCOMM", 0, KEY_QUERY_VALUE, &hKey); 
if(lReg!=ERROR_SUCCESS) 
{ 
  AfxMessageBox(L"Open Registry Error!\n"); 
  return; 
} 

lReg=RegQueryInfoKeyA(hKey, 
  NULL, 
  NULL, 
  NULL, 
  NULL, 
  NULL, 
  NULL, 
  &dwValueNumber, //返回和hKey关联的值 
  &MaxValueLength, 
  NULL, 
  NULL, 
  NULL); 
if(lReg!=ERROR_SUCCESS) //没有成功 
{ 
  AfxMessageBox(L"Getting Info Error!\n"); 
  return; 
} 

LPSTR  pValueName,pCOMNumber; 
DWORD  cchValueName,dwValueSize=6; 

for(DWORD  i=0;i < dwValueNumber;i++) 
{ 
  cchValueName=MaxValueLength+1; 
  dwValueSize=6; 
  pValueName=(LPSTR)VirtualAlloc(NULL,cchValueName,MEM_COMMIT,PAGE_READWRITE); 
  lReg=RegEnumValueA(hKey, 
   i, 
   pValueName, 
   &cchValueName, 
   NULL, 
   NULL, 
   NULL, 
   NULL); 

  if((lReg!=ERROR_SUCCESS)&&(lReg!=ERROR_NO_MORE_ITEMS)) 
  { 
   AfxMessageBox(L"Enum Registry Error or No More Items!\n"); 
   continue; 
  } 

  pCOMNumber=(LPSTR)VirtualAlloc(NULL,6,MEM_COMMIT,PAGE_READWRITE); 
  lReg=RegQueryValueExA(hKey, 
   pValueName, 
   NULL, 
   NULL, 
   (LPBYTE)pCOMNumber, 
   &dwValueSize); 

  if(lReg!=ERROR_SUCCESS) 
  { 
   AfxMessageBox(L"Can not get the name of the port"); 
   continue; 
  } 
  CString strCommList;
  //AfxMessageBox(pCOMNumber);
  CharToUnicode(pCOMNumber,&strCommList);
  //m_ctlPort.AddString(strCommList);
  BOOL m_bInsert=0;

  if(((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->GetCount()==0) ((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->AddString(strCommList);
  else
  {
   CString strTemp=strCommList;
   strCommList.TrimLeft(L"COM");
   for(int icurrent=0;icurrent<((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->GetCount();icurrent++) { CString strCurrent; ((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->GetLBText(icurrent,strCurrent);
    strCurrent.TrimLeft(L"COM");
    if(_ttol(strCurrent)>_ttol(strCommList))
    {
     ((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->InsertString(icurrent,strTemp);
     m_bInsert = 1;
     break;
    }
   }
   if(!m_bInsert)
    ((CComboBox*)GetDlgItem(IDC_CMBREADERCOM))->InsertString(icurrent,strTemp);
  }

  VirtualFree(pValueName,0,MEM_RELEASE); 
  VirtualFree(pCOMNumber,0,MEM_RELEASE); 
} 
}
int CPageSetCom::CharToUnicode(char *pchIn, CString *pstrOut)
{
int nLen;
    WCHAR *ptch;
    if(pchIn == NULL)
    {
        return 0;
    }
    nLen = MultiByteToWideChar(CP_ACP, 0, pchIn, -1, NULL, 0);
    ptch = new WCHAR[nLen];
    MultiByteToWideChar(CP_ACP, 0, pchIn, -1, ptch, nLen);
    pstrOut->Format(_T("%s"), ptch);

    delete [] ptch;
    return nLen;
}