教程 | 设备查找类CxDeviceFind & CxDeviceMapFind

CxDeviceFind的使用如下：

void CUsbScannerDlg::SearchDevice(LPGUID lpguidDev)
{
    m_list1.ResetContent();

    HANDLE hDevice;
    TCHAR szPath[MAX_PATH] = {0};
    GUID guidCls;
    CxDeviceFind finder;
    BOOL bRet = finder.FindDevice(lpguidDev);
    while (bRet)
    {
        finder.GetDevicePath(szPath);
        m_list1.AddString(szPath);

        hDevice = CreateFile(szPath, GENERIC_READ | GENERIC_WRITE, 0,
                                NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
        if (hDevice != INVALID_HANDLE_VALUE)
        {
            CloseHandle(hDevice);
            m_list1.AddString(_T("Can be open"));
        }
        else
            m_list1.AddString(_T("Can not be open"));
        
        finder.GetDeviceFriendlyName(szPath);
        m_list1.AddString(szPath);
        
        finder.GetDeviceLocationInfo(szPath);
        m_list1.AddString(szPath);
        
        finder.GetDeviceDescription(szPath);
        m_list1.AddString(szPath);
        
        finder.GetDeviceHardwareID(szPath);
        m_list1.AddString(szPath);
        
        finder.GetDeviceInstanceID(szPath);
        m_list1.AddString(szPath);
        
        finder.GetClassGuid(&guidCls);
        sprintf(szPath, "guid_cls[%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x]",
            guidCls.Data1, guidCls.Data2, guidCls.Data3,
            guidCls.Data4[0], guidCls.Data4[1], guidCls.Data4[2], guidCls.Data4[3],
            guidCls.Data4[4], guidCls.Data4[5], guidCls.Data4[6], guidCls.Data4[7]);
        m_list1.AddString(szPath);
        
        m_list1.AddString("");
        m_list1.AddString("-->Next<--");
        bRet = finder.FindNextDevice();
    }
    finder.Close();
}

然后在需要的地方调用此函数，例如：

void CUsbScannerDlg::OnBtnUsb() 
{
    // TODO: Add your control notification handler code here
    GUID guid = GUID_DEVINTERFACE_USB_DEVICE;
    SearchDevice(&guid);
}

其中 GUID guid 可以是以下多种设备类型的GUID
GUID_DEVINTERFACE_USB_DEVICE

GUID_DEVINTERFACE_COMPORT

GUID_DEVINTERFACE_PARALLEL

GUID_BTHPORT_DEVICE_INTERFACE

等等，更多设备类型的GUID可参见MSDN。

CxDeviceMapFind的使用如下：

int xApi::GetInstalledSerialPort(LPBYTE lpbtPort, int nMaxCount)
{
    int nPrefixLen = lstrlen(_T("COM")), nSerialPort, i = 0, j = 0;
    TCHAR szPath[MAX_PATH] = {0};

    CxDeviceMapFind dev_map_find;
    GUID guid = GUID_DEVINTERFACE_COMPORT;
    BOOL bRet = dev_map_find.FindDeviceMap(&guid);
    while (bRet)
    {
        dev_map_find.GetDevicePath(szPath);
        if (lstrlen(szPath) > nPrefixLen)
        {
            nSerialPort = _ttoi(&szPath[nPrefixLen]);
            if (i < nMaxCount)
                lpbtPort[i++] = nSerialPort;
            j++;
        }
        
        bRet = dev_map_find.FindNextDeviceMap();
    }
    dev_map_find.Close();

    return j;
}

然后在需要的地方调用此函数，例如：

void CCaloricControllerDlg::OnDropdownCmbSerial() 
{
    // TODO: Add your control notification handler code here
    m_cmbSerial.ResetContent();
    CString str;
    BYTE btPort[MAXBYTE];
    int nCount = xApi::GetInstalledSerialPort(btPort, MAXBYTE);
    m_cmbSerial.ResetContent();
    for (int i=0; i<nCount; i++)
    {
        str.Format(_T("COM%d"), (int)btPort[i]);
        m_cmbSerial.AddString(str);
    }    
}

目前CxDeviceMapFind只支持以下GUID

GUID_DEVINTERFACE_COMPORT

GUID_DEVINTERFACE_PARALLEL

　　精练的代码不需要过多解释，你们懂的。To be continued...

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