Qt：监控设备插入拔除

在nativeEvent里面解析系统消息，获取USB等设备的插入和拔出事件。

使用步骤：

窗口初始化时使用RegisterDeviceNotification注册设备通知
在nativeEvent函数里面解析系统消息
窗口关闭时，使用UnregisterDeviceNotification关闭指定的设备通知句柄

关键代码如下：

注册设备通知

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
    ui->setupUi(this);

    DEV_BROADCAST_DEVICEINTERFACE notificationFilter;
    ZeroMemory(&notificationFilter, sizeof(notificationFilter));
    notificationFilter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
    notificationFilter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
    notificationFilter.dbcc_classguid = GUID_DEVINTERFACE_USB_DEVICE;
    devNotify = RegisterDeviceNotification(reinterpret_cast<HANDLE>(this->winId()), &notificationFilter, DEVICE_NOTIFY_WINDOW_HANDLE);// DEVICE_NOTIFY_WINDOW_HANDLE); DEVICE_NOTIFY_ALL_INTERFACE_CLASSES
    if (!devNotify) {
        qWarning() << "RegisterDeviceNotification failed";
    }
}

解析系统消息

bool MainWindow::nativeEvent(const QByteArray &eventType, void *message, qintptr *result) {
    MSG *msg = (MSG *) message;
    if (msg->message == WM_DEVICECHANGE) {
        auto hdr = reinterpret_cast<PDEV_BROADCAST_HDR>(msg->lParam);
        switch (msg->wParam) {
            case DBT_DEVICEARRIVAL:
                if (hdr->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
                    auto info = (PDEV_BROADCAST_DEVICEINTERFACE) hdr;
                    auto devName = QString::fromWCharArray(info->dbcc_name);
                    qDebug() << "+: " << devName;
                }
                break;
            case DBT_DEVICEREMOVECOMPLETE:
                if (hdr->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
                    auto info = (PDEV_BROADCAST_DEVICEINTERFACE) hdr;
                    auto devName = QString::fromWCharArray(info->dbcc_name);
                    qDebug() << "-: " << devName;
                }
                break;
        }
    }
    return false;
}

插拔串口时，输出如下：

+:  "\\\\?\\USB#VID_1A86&PID_7523................................."
-:  "\\\\?\\USB#VID_1A86&PID_7523................................."

关闭指定的设备通知句柄

MainWindow::~MainWindow() {
    if (devNotify) {
        UnregisterDeviceNotification(devNotify);
    }
}

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原文链接：https://www.jianshu.com/p/9ec8a56c3f0f