Hi,

I'm using CyUSB.NET from a Windows Service and it needs to detect devices that are attached and removed.

I find that the service does not get the USBDeviceList.DeviceAttached or DeviceRemoved events. However, if I move the code to a process then it does get these events.

Is there a way for a Windows service to get these events from USBDeviceList?

Thanks,

Ben

1. Please post your code here so that I can get a better idea of how you're implementing it.

2. Why do want to get the notification specifically through service

Regards,

Anand

Hi,

For Q2 - The structure of our application needs to use a Windows service to detect the USB devices.

For Q1 - I've attached a simplified VS2008 solution with what I am trying to do from a Windows service.

The CyUsbApp project has a Windows application that succesfully detects devices being added/removed.

The ServerService project has the code that creates the service (you can install the service using the InstallUtil utility). This logs to the event log when it detects a device being added/removed.

Both projects use the same code to detect devices. This code is in UsbManager.cs:

        private void RegisterDeviceNotifications()

        {

            mUsbDeviceList = new USBDeviceList(CyConst.DEVICES_CYUSB);
            mUsbDeviceList.DeviceAttached += new EventHandler(mUsbDeviceList_DeviceAttached);
            mUsbDeviceList.DeviceRemoved += new EventHandler(mUsbDeviceList_DeviceRemoved);
        }
 

USBDeviceList is populated with entries when the service starts. But I can't get the service to receive events from USBDeviceList.DeviceAttached() or USBDeviceList.DeviceRemoved().

Cheers,
Ben

Well, I found a work around to getting a service to recognise attached/detached devices.

Basically, you need to register a handler in the service for device notifications (instead of getting these events from USBDeviceList). Then handle the DEVICEARRIVAL and DEVICEREMOVECOMPLETE events when a device is attached/detached.

I found that I had to create a new USBDeviceList object each time a device is attached or detached. The one that I create at start up doesn't ever recognise new devices.

I also found that subscribing to the USBDeviceList.DeviceAttached and DeviceRemoved events would cause the device detached events to be delayed for some reason.

Anyway, hopefully the above information helps anyone else who is stuck with the same issue.

 Hi,

Glad to hear that the problem is resolved, and thank you for posting the solution here. It might help some one in need later.

Regards,

Gayathri