Qt combat | how to access the USB device information?

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文章出处：Qt小罗

整理：李肖遥

1 需求描述

1. 实现USBHotplug state testing of the equipment;

2. 可识别USB设备信息,例如PID、VID、设备序列号等.

几年前在CSDN上分享过,被CSDN恶心到了,Randomly set points,Disguised to allow users to charge money,Now rearrange the code to share,希望能帮到需要的人.

2 设计思路

2.1 获取USBdevice information？

经过查询,QtDevice-related information can be obtained through local events,The event function prototype used is：

bool QWidget::nativeEvent(const QByteArray &eventType, void *message, long *result)

官方说明：This special event handler can be reimplemented in subclasses,To receive in the message parameter passed byeventType标识的本机平台事件.In the reimplementation of this function,if you want to stopQt正在处理的事件,请返回true并设置result,The result parameter is onlyWindows上有意义.如果返回false,This native event will be delivered backQt,Qtconvert the event toQtevent and send it to the window.

注意：It is only when the window has a local window handle,events are delivered to this event handler.

很容易理解吧,对于widget窗口而言,This event is the source,QtPackaged events come from here,如果直接返回trueThe interface will not be displayed,有兴趣的朋友可以试试.另外,Found that the event is notQWidget的,So only the window interface has,The handle of the window can be accessed viaQWidget::winId获取到,Behind the register equipment will be used.

2.2 准备工作？

如果只是重写nativeEvent是不够的,No device information can be obtained,Can only identify hotplug state.要识别USBDevice information needs to be usedGUID,pre-defined deviceGUID,re-register the device,Only after the registration is complete can the local events of the corresponding device be obtained,To obtain device information through events.

GUID（全称：Globally Unique Identifier）全局唯一标识符,在windows上使用GUID来管理设备,驱动,总线,类型,块设备,电源等.

2.3 Common hardware devicesGUID

Identifier	Class GUID
GUID_DEVINTERFACE_USB_DEVICE	{A5DCBF10-6530-11D2-901F-00C04FB951ED}
GUID_DEVINTERFACE_USB_HOST_CONTROLLER	{A5DCBF10-6530-11D2-901F-00C04FB951ED}
GUID_DEVINTERFACE_USB_HUB	{F18A0E88-C30C-11D0-8815-00A0C906BED8}
GUID_DEVINTERFACE_NET	{CAC88484-7515-4C03-82E6-71A87ABAC361}
GUID_DEVINTERFACE_DISK	{53F56307-B6BF-11D0-94F2-00A0C91EFB8B}
GUID_DEVINTERFACE_CDROM	{53F56308-B6BF-11D0-94F2-00A0C91EFB8B}
GUID_DEVINTERFACE_KEYBOARD	{884B96C3-56EF-11D1-BC8C-00A0C91405DD}
GUID_DEVINTERFACE_MOUSE	{378DE44C-56EF-11D1-BC8C-00A0C91405DD}
GUID_DEVINTERFACE_IMAGE	{6BDD1FC6-810F-11D0-BEC7-08002BE2092F}
GUID_BTHPORT_DEVICE_INTERFACE	{0850302A-B344-4fda-9BE9-90576B8D46F0}
太多了,网上可以搜到,这里就不一一列出.

3 代码实现

windowsProvides an interface to register devices with the system,After registrationU盘插拔（或其它volume增删）的时候,will be sent to the registered windowWM_DEVICECHANGE消息：
HDEVNOTIFY WINAPI RegisterDeviceNotification(
__in HANDLE hRecipient, // Can be a window handle or a service handle
__in LPVOID NotificationFilter,
__in DWORD Flags // 制定hRecipient是窗口句柄,or service handle
);

1. 先注册设备,这样才能接收到消息,代码如下：

   void Dialog::registerDevice()
   {
       const GUID GUID_DEVINTERFACE_LIST[] = {
           { 0xA5DCBF10, 0x6530, 0x11D2, { 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED } }, //USB设备的GUID
           { 0x53f56307, 0xb6bf, 0x11d0, { 0x94, 0xf2, 0x00, 0xa0, 0xc9, 0x1e, 0xfb, 0x8b } }};
   
   
       HDEVNOTIFY hDevNotify;
       DEV_BROADCAST_DEVICEINTERFACE NotifacationFiler;
       ZeroMemory(&NotifacationFiler,sizeof(DEV_BROADCAST_DEVICEINTERFACE));
       NotifacationFiler.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
       NotifacationFiler.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
   
   
       for (int i = 0; i < sizeof(GUID_DEVINTERFACE_LIST)/sizeof(GUID); i++)  {
           NotifacationFiler.dbcc_classguid = GUID_DEVINTERFACE_LIST[i];
           hDevNotify = RegisterDeviceNotification((HANDLE)this->winId(), &NotifacationFiler, DEVICE_NOTIFY_WINDOW_HANDLE);
           if (!hDevNotify) {
               qCritical() << QStringLiteral("注册失败！");
           }
       }
   }

2. Get news and parse through local events,代码如下：

bool Dialog::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
    Q_UNUSED(eventType);
    Q_UNUSED(result);


    MSG *msg = reinterpret_cast<MSG *>(message);


    int msgType = msg->message;
    if (WM_DEVICECHANGE == msgType) {
        PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)msg->lParam;
        switch (msg->wParam) {
        case DBT_DEVICEARRIVAL:
        {
            if (DBT_DEVTYP_VOLUME == lpdb->dbch_devicetype) {
                PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb;
                if (0 == lpdbv->dbcv_flags) { //优盘
                    QString USBDisk = QString(this->firstDriveFromMask(lpdbv ->dbcv_unitmask));
                    ui->labelShowMsg->setText(QString(QStringLiteral("已检测到USB设备插入--盘符:<%1>")).arg(USBDisk));
                } else if (DBTF_MEDIA == lpdbv->dbcv_flags) {
                    qDebug() << "CD_Arrived.";
                }


            } else if (DBT_DEVTYP_DEVICEINTERFACE == lpdb->dbch_devicetype)  {


                PDEV_BROADCAST_DEVICEINTERFACE pDevInf  = (PDEV_BROADCAST_DEVICEINTERFACE)lpdb;
                QString name = QString::fromWCharArray(pDevInf->dbcc_name);
                if (!name.isEmpty()) {
                    if (name.contains("USBSTOR")) {
                        QStringList listAll = name.split('#');
                        QStringList listInfo = listAll.at(1).split('&');
                        m_usbInfoList.append(listInfo.at(1).mid(4)); //设备制造商 3
                        m_usbInfoList.append(listInfo.at(2).mid(5)); //设备型号 4
                        m_usbInfoList.append(listInfo.at(3).mid(4)); //设备版本 5
                    } else {
                        m_usbInfoList.clear();
                        QStringList listAll = name.split('#');
                        QStringList listID = listAll.at(1).split('&');
                        m_usbInfoList.append(listID.at(0).right(4)); //vid 0
                        m_usbInfoList.append(listID.at(1).right(4)); //pid 1
                        m_usbInfoList.append(listAll.at(2)); //设备序列号 2
                    }
                }


                display();
            }
        }
            break;
        case DBT_DEVICEREMOVECOMPLETE:
        {
            if (DBT_DEVTYP_VOLUME == lpdb->dbch_devicetype) {
                PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb;
                if (0 == lpdbv->dbcv_flags) {
                    ui->labelShowMsg->setText(QString(QStringLiteral("USB设备已拔出！")));
                    QTimer::singleShot(1000, ui->labelShowMsg, SLOT(clear()));
                }


                if (DBTF_MEDIA == lpdbv->dbcv_flags) {
                    ui->labelShowMsg->setText("CD_Removed.");
                }
            }
        }
            break;
        }
    }


    return false;
}

折叠

补充下,获取到的USBThe original data of device information is as follows,Through the above code parsing,然后显示到界面上.

"\\\\?\\USB#VID_0951&PID_1666#E0D55EA574B4F371679B1A6D#{a5dcbf10-6530-11d2-901f-00c04fb951ed}"
"\\\\?\\USBSTOR#Disk&Ven_Kingston&Prod_DataTraveler_3.0&Rev_#E0D55EA574B4F371679B1A6D&0#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}"

发现没有,这个GUIDIs it the same as what we registered?,feel it.If you want to get information about other devices,Registration is indispensable,不然就获取不到.再有一个就是,Equipment information is not an event would get out of,从上可以看出,It takes two events here to get the complete information,That is, registered two devices,可以尝试将GUID_DEVINTERFACE_LISTRemove a listGUID,结果是USBEquipment information is not complete.

3 总结

By registering the device、receive local events、Parse the event message,Finally, device information can be obtained.If you want to further implement special functions,Such as custom borderless stretching、移动等,Can also be achieved by local events,这需要对windowsThe message mechanism can be further studied.当然也可以使用QtEncapsulated events for processing,都是事件,What kind of tricks you can play depends on your own ability..到这里对windowsThere should be a preliminary understanding of the message mechanism,还是那句话,Have a good start is always important.

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