Fingerprint capturing with DigitalPersona 5300 Reader. How to detect the device in a windows service?

Question

I'm trying to integrate the U.are.U 5300 Fingerprint device in my web application using windows service. I'm using SignalR to communicate back and forth, but that isn't a problem. I've a small piece of code which returns the first device that is attached to the machine.

 public Reader GetReader()
        {
            if (this._reader == null)
            {
                this._reader = ReaderCollection.GetReaders()[0];
                var openResult = this._reader.Open(Constants.CapturePriority.DP_PRIORITY_COOPERATIVE);
                _res = this._reader.GetDefaultRes();
            }
            return this._reader;
        }

I de-compiled the hardware dll and this is the actual code that they use (not sure if this will help).

 public static ReaderCollection GetReaders()
        {
            unsafe
            {
                ReaderCollection readerCollections;
                using (Tracer tracer = new Tracer("ReaderCollection::GetReaders"))
                {
                    Constants.ResultCode resultCode = Constants.ResultCode.DP_DEVICE_FAILURE;
                    if (ReaderCollection.instance == null)
                    {
                        ReaderCollection.instance = new ReaderCollection();
                        try
                        {
                            ReaderCollection.instance.m_items = new List<Reader>();
                            NativeMethods.SetDllDirectory();
                            resultCode = NativeMethods.dpfpdd_init();
                            tracer.TraceResult((int)resultCode);
                            if (!resultCode.Equals(Constants.ResultCode.DP_SUCCESS) && (int)resultCode != 1)
                            {
                                ReaderCollection.instance = null;
                                throw new SDKException(resultCode, "Could not initialize driver", new InvalidOperationException());
                            }
                            resultCode = NativeMethods.dpfj_select_engine((IntPtr)0, Constants.EngineType.DP_ENGINE_DPFJ);
                            tracer.TraceResult((int)resultCode);
                            if (!resultCode.Equals(Constants.ResultCode.DP_SUCCESS))
                            {
                                ReaderCollection.instance = null;
                                throw new SDKException(resultCode, "Could not slect Engine Type", new InvalidOperationException());
                            }
                        }
                        catch (Exception exception)
                        {
                            tracer.Trace(exception.Message);
                            ReaderCollection.instance = null;
                            throw new SDKException(Constants.ResultCode.DP_FAILURE, string.Empty, null);
                        }
                    }
                    resultCode = Constants.ResultCode.DP_FAILURE;
                    int num = 0;
                    NativeMethods.DPFPDD_DEV_INFO[] dPFPDDDEVINFOArray = null;
                    try
                    {
                        resultCode = NativeMethods.dpfpdd_query_devices(ref num, dPFPDDDEVINFOArray);
                        if (!num.Equals(0))
                        {
                            dPFPDDDEVINFOArray = new NativeMethods.DPFPDD_DEV_INFO[num];
                            dPFPDDDEVINFOArray[0].size = Marshal.SizeOf(dPFPDDDEVINFOArray[0]);
                            resultCode = NativeMethods.dpfpdd_query_devices(ref num, dPFPDDDEVINFOArray);
                            tracer.Trace(string.Format("dpfpdd_query_devices called, count is {0}", num.ToString()));
                        }
                        ReaderCollection.Refresh(dPFPDDDEVINFOArray);
                        readerCollections = ReaderCollection.instance;
                    }
                    catch (Exception exception1)
                    {
                        tracer.Trace(exception1.Message);
                        throw new SDKException(Constants.ResultCode.DP_FAILURE, string.Empty, null);
                    }
                }
                return readerCollections;
            }
        }

This code works fine in a windows form application (desktop application). But it is not able to detect my device in a windows service.

• I've set the windows service permission as 'Local System'
• Enabled the setting to 'Allow service to interact with desktop'

Do we have any special permissions (windows or app level) that we need to set to detect the device or interact through a windows service?

Answer 1

Got the answer: By default the U.are.U SDK installs the DigitalPersona Authenication Service, all you need to do is disable this service!