private void ScanLoop()
{
var culture = CultureInfo.InvariantCulture;
Thread.CurrentThread.CurrentCulture = culture;
Thread.CurrentThread.CurrentUICulture = culture;
// The read has a timeout parameter, so every X milliseconds
// we check if the user wants us to continue scanning.
while (asyncScanOn)
{
try
{
IntPtr device_info = HidApi.hid_enumerate(vendorId, productId);
bool device_on_bus = device_info != IntPtr.Zero;
// freeing the enumeration releases the device,
// do it as soon as you can, so we dont block device from others
HidApi.hid_free_enumeration(device_info);
if (device_on_bus && !deviceConnected)
{
// just found new device
deviceConnected = true;
if (DeviceArrived != null)
{
DeviceArrived(this, EventArgs.Empty);
}
}
if (!device_on_bus && deviceConnected)
{
// just lost device connection
deviceConnected = false;
if (DeviceRemoved != null)
{
DeviceRemoved(this, EventArgs.Empty);
}
}
}
catch (Exception e)
{
// stop scan, user can manually restart again with StartAsyncScan()
asyncScanOn = false;
}
// when read 0 bytes, sleep and read again
Thread.Sleep(ScanIntervalInMillisecs);
}
}
// scanning for device when it is open by another process will return false
public static bool ScanOnce(ushort vid, ushort pid)
{
return(HidApi.hid_enumerate(vid, pid) != IntPtr.Zero);
}
