Question

我对窗口编程很新。我在QT5中实现了一个托盘，当特定设备与PC连接/断开时，该托盘显示一条消息。我创建了仅限消息的窗口，用于接收USB设备的断开/连接。一切都好，直到这里，我收到的消息是每次插拔设备的电缆/从电脑上拔掉两次。（不要认为Windows 10在发送它时是如此慷慨2次）

我的问题：为什么会发生这种情况，不应该只发生一次吗？

**已经回答了这个问题，因为该设备显示为HID和USB，其PID / VID与此处编程的相同。

以下是代码：

GUID InterfaceClassGuid = { 0x745a17a0, 0x74d3, 0x11d0, { 0xb6, 0xfe, 0x00, 0xa0, 0xc9, 0x0f, 0x57, 0xda } };

// Registration method

void usbMessage::RegisterNotification()
{
    // Set GUID filter data
    if (usbCNCMsg != nullptr) {
        _pDevIF = (DEV_BROADCAST_DEVICEINTERFACE *)malloc(sizeof(DEV_BROADCAST_DEVICEINTERFACE));
        memset(_pDevIF, 0, sizeof(DEV_BROADCAST_DEVICEINTERFACE));
        _pDevIF->dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);

        _pDevIF->dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
        _pDevIF->dbcc_classguid = InterfaceClassGuid;

        // Register for notifications
        _hNotifyDev = RegisterDeviceNotification(this->GetSafeHwnd(), _pDevIF, DEVICE_NOTIFY_ALL_INTERFACE_CLASSES);
        if (!_hNotifyDev) {
            AfxMessageBox(CString("Can't register device notification: ")
                + _com_error(GetLastError()).ErrorMessage(), MB_ICONEXCLAMATION);
        }
    } else {
        qDebug() << "There was no connection msg Obj passed. MFC msg queue not enabled.";
    }
}


bool usbMessage::matchVidPid(QString dbcc_name)
{
    QString devicePid;
    QString deviceVid;

    int indx = dbcc_name.indexOf("#");
    int indx2 = dbcc_name.indexOf("&");
    deviceVid = dbcc_name.mid(indx  + 1, PID_VID_LENGTH);
    devicePid = dbcc_name.mid(indx2 + 1, PID_VID_LENGTH);

    if (deviceVid == VID_STRNG &&
        devicePid == PID_STRNG) {
        return true;
    }

    return false;
}


LRESULT usbMessage::OnMyDeviceChange(WPARAM wParam, LPARAM lParam)
{
    PDEV_BROADCAST_DEVICEINTERFACE pDevInf;

    if (DBT_DEVICEARRIVAL == wParam || DBT_DEVICEREMOVECOMPLETE == wParam) {
        PDEV_BROADCAST_HDR pHdr = (PDEV_BROADCAST_HDR)lParam;
        switch (pHdr->dbch_devicetype) {
        case DBT_DEVTYP_DEVICEINTERFACE:
            pDevInf = (PDEV_BROADCAST_DEVICEINTERFACE)pHdr;
            if (matchVidPid(QString::fromWCharArray(pDevInf->dbcc_name))) {
                if (DBT_DEVICEARRIVAL == wParam) {                    
                    this->usbCNCMsg->sendMessageConnected(trayMsgHelper::getDeviceConnectedMsg());
                }

                if (DBT_DEVICEREMOVECOMPLETE == wParam) {
                    this->usbCNCMsg->sendMessageDisconnected(trayMsgHelper::getDeviceDisconnectedMsg());
                }
            }
            break;
        }
    }
    return 0;
}

谢谢！

Windows上的USB设备连接触发了2次

0 个答案: