windows Qt如何知道新的USB存储设备何时连接？
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How to know when a new USB storage device is connected in Qt?
提问by Skilldrick
I want to know when a USB device is connected to the computer that my Qt application is running on (in Windows). In my main QWidget, I've reimplemented winEventFilterlike this:
我想知道 USB 设备何时连接到运行我的 Qt 应用程序的计算机（在 Windows 中）。在我的主要 QWidget 中，我重新实现了winEventFilter这样：
bool winEventFilter ( MSG * msg, long * result ) {
qDebug() << msg;
return false;
}
I'd expect qDebug to send at least something when I connect a USB device, but I don't get anything.
当我连接 USB 设备时，我希望 qDebug 至少发送一些东西，但我什么也没收到。
I'm guessing that I'm fundamentally misunderstanding the process here - this is my first Qt app!
我猜我从根本上误解了这里的过程 - 这是我的第一个 Qt 应用程序！
采纳答案by brader24
I believe what you may be missing is the call to register for device notification. Here is code that I use to do the same thing, though I override the winEvent() method of the QWidget class and not the winEventFilter.
我相信您可能缺少的是注册设备通知的电话。这是我用来做同样事情的代码，尽管我覆盖了 QWidget 类的 winEvent() 方法而不是 winEventFilter。
// Register for device connect notification
DEV_BROADCAST_DEVICEINTERFACE devInt;
ZeroMemory( &devInt, sizeof(devInt) );
devInt.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
devInt.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
devInt.dbcc_classguid = GUID_DEVINTERFACE_VOLUME;
m_hDeviceNotify =
RegisterDeviceNotification( winId(), &devInt, DEVICE_NOTIFY_WINDOW_HANDLE );
if(m_hDeviceNotify == NULL)
{
qDebug() << "Failed to register device notification";
} // end if
NOTE: You will most likely need to change the values of the DEV_BROADCAST_DEVICEINTERFACEto fit your needs.
注意：您很可能需要更改 的值DEV_BROADCAST_DEVICEINTERFACE以满足您的需要。
EDIT: To use this code you will need to include the proper header files and perform the proper setup. DEV_BROADCAST_DEVICEINTERFACErequires the Dbt.h header to be included. Also, the focal point of this code is on the RegisterDeviceNotification function. Info is available on MSDN
编辑：要使用此代码，您需要包含正确的头文件并执行正确的设置。 DEV_BROADCAST_DEVICEINTERFACE需要包含 Dbt.h 标头。此外，此代码的重点是 RegisterDeviceNotification 函数。信息可在MSDN 上找到
回答by Dark Star1
I'm working along the same lines but in C#.
我正在沿着相同的路线工作，但在 C# 中。
you need to register your application with the system (look at the RegisterHidNotification() function). Mine looks like this: `
您需要向系统注册您的应用程序（查看 RegisterHidNotification() 函数）。我的看起来像这样：`
void RegisterHidNotification() //Register this application to recieve all USB device notices
{
BroadcastHeader dbi = new BroadcastHeader();
int size = Marshal.SizeOf(dbi);
dbi.Size = size;
dbi.Type = DeviceType.DeviceInterface;
**dbi.Classguid = GUID_DEVINTERFACE_USB_DEVICE**;
dbi.Name = 0;
IntPtr buffer = Marshal.AllocHGlobal(size);
Marshal.StructureToPtr(dbi, buffer, true);
IntPtr r = RegisterDeviceNotification(this.Handle, buffer, (int)DeviceEvents.regWindowHandle);
if (r == IntPtr.Zero)
statusLabel.Text = GetLastError().ToString();
}`
The most important part of the function is the bit I've highlighted in bold (or at least tried to). Defined as: public Guid GUID_DEVINTERFACE_USB_DEVICE = new Guid("A5DCBF10-6530-11D2-901F-00C04FB951ED");Hope you can adapt it to your application.
该函数最重要的部分是我用粗体突出显示的部分（或至少尝试过）。定义为：public Guid GUID_DEVINTERFACE_USB_DEVICE = new Guid("A5DCBF10-6530-11D2-901F-00C04FB951ED");希望您可以将其调整到您的应用程序中。
回答by IMAN4K
You can easily reimplement QWidget::nativeEvent(const QByteArray &eventType, void *message, long *result)and check for device connection :
您可以轻松地重新实现QWidget::nativeEvent(const QByteArray &eventType, void *message, long *result)和检查设备连接：
#ifdef Q_OS_WIN
#include <Dbt.h>
#endif
bool MainWindow::nativeEvent(const QByteArray &eventType, void *message, long *result) {
#ifdef Q_OS_WIN
MSG* msg = reinterpret_cast<MSG*>(message);
if (msg->message == WM_DEVICECHANGE) {
switch (msg->wParam) {
case DBT_DEVICEARRIVAL:
qDebug() << "connected";
break;
case DBT_DEVICEREMOVECOMPLETE:
qDebug() << "disconnected";
break;
default:
break;
}
}
#endif // Q_OS_WIN
return false;
}
