获取计算机所有串口的VC代码

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，代码如下：
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;
}