GpsClient2/ComPortGpsClient.cs

using GpsClient2.EventArguments;
using GpsClient2.Exceptions;
using GpsClient2.Model;
using GpsClient2.NmeaMessages;
using System;
using System.ComponentModel;
using System.IO.Ports;
using System.Threading.Tasks;

namespace GpsClient2 {
    public class ComPortGpsClient : BaseGpsClient {
        #region Private Properties

        private readonly NmeaParser _parser = new NmeaParser();
        private SerialPort _serialPort;

        private DateTime? _previousReadTime;
        private readonly BackgroundWorker worker = new BackgroundWorker();
        private ComPortInfo data = null;
        #endregion

        #region Constructors

        public ComPortGpsClient(ComPortInfo connectionData) : base(GpsType.ComPort, connectionData) {
        }

        public ComPortGpsClient(BaseGpsInfo connectionData) : base(GpsType.ComPort, connectionData) {
        }

        #endregion

        #region Connect and Disconnect

        public override bool Connect() {
            data = (ComPortInfo)GpsInfo;

            IsRunning = true;
            OnGpsStatusChanged(GpsStatus.Connecting);
            _serialPort = new SerialPort(data.ComPort, data.BaudRate, Parity.None, 8, StopBits.One);

            // Attach a method to be called when there
            // is data waiting in the port's buffer
            //_serialPort.DataReceived += port_DataReceived;
            try {
                // Begin communications
                _serialPort.Open();

                OnGpsStatusChanged(GpsStatus.Connected);
                // Enter an application loop to keep this thread alive
                worker.DoWork += Worker_DoWork;
                worker.RunWorkerAsync();
                return true;
            } catch {
                Disconnect();
                throw;
            }
        }

        private async void Worker_DoWork(object sender, DoWorkEventArgs e) {
            while (_serialPort.IsOpen) {
                await Task.Delay(data.ReadFrequency);
                //Thread.Sleep(data.ReadFrequenty);
                processData();
            }
        }

        public override bool Disconnect() {
            _serialPort.Close();
            IsRunning = false;
            OnGpsStatusChanged(GpsStatus.Disabled);
            return true;
        }
        #endregion

        #region Location Callbacks

        private void port_DataReceived(object sender, SerialDataReceivedEventArgs e) {
            processData();
        }

        private void processData() {
            try {
                var readString = _serialPort.ReadExisting().Trim();

                foreach (string sentence in readString.Split(new string[] { Environment.NewLine }, StringSplitOptions.None)) {
                    if (sentence.Length > 0 && sentence.StartsWith("$") && sentence.Contains("*")) {
                        parseSentence(sentence.Trim());
                    }
                }
            } catch (Exception ex) {
                Console.WriteLine(" ==> " + ex.Message);
            }
        }

        private void parseSentence(string sentence) {
            if (sentence.StartsWith("$GPGSV")) { return; }  // Ignore all $GPGSV messages
            //Console.WriteLine(sentence);
            try {
                OnRawGpsDataReceived(sentence);
                var result = _parser.Parse(sentence);
                if (result == null) { return; }

                if (typeof(GprmcMessage) != result.GetType()) return;
                if (_previousReadTime != null && GpsInfo.ReadFrequency != 0 && ((GprmcMessage)result).UpdateDate.Subtract(new TimeSpan(0, 0, 0, 0, GpsInfo.ReadFrequency)) <= _previousReadTime) return;
                OnGpsDataReceived(new GpsDataEventArgs((GprmcMessage)result));
            } catch (UnknownTypeException ex) {
                Console.WriteLine(" ==> " + ex.Message + " : " + sentence);
            } catch (ArgumentException ex) {
                Console.WriteLine(" ==> " + ex.Message + " : " + sentence);
            }
        }
        #endregion


        #region "Find My GPS Device Methods"
        public async Task<bool> FindGps() {
            int[] bauds = { 9600, 4800 };

            foreach (string comPort in SerialPort.GetPortNames()) {
                foreach (int baud in bauds) {
                    if (await IsGpsPort(comPort, baud)) {
                        GpsInfo = new ComPortInfo(comPort, baud);
                        return true;
                    }
                }
            }

            return false;
        }

        private static async Task<bool> IsGpsPort(string comPort, int baudRate) {
            bool result = await Task.Run(() => {
                Console.Write("Attempting to locate GPS on " + comPort + ":" + baudRate + "...");
                SerialPort serial = new SerialPort(comPort, baudRate, Parity.None, 8, StopBits.One);
                serial.ReadTimeout = 3000;
                try {
                    serial.Open();
                    Console.Write(" Connected. Listening for NMEA Sentences...");
                } catch (Exception ex) {
                    Console.WriteLine(" Error: " + ex.Message);
                    return false;
                }

                string sData = "";
                while (true) {
                    string s;
                    try {
                        s = serial.ReadLine();
                    } catch (Exception ex) {
                        serial.Close();
                        Console.WriteLine(" Error: " + ex.Message);
                        return false;
                    }

                    if (string.IsNullOrEmpty(s)) { return false; }
                    sData += s + Environment.NewLine;

                    if (sData.Length > 1500) {

                        if (sData.Contains("$GPRMC") || sData.Contains("$GPGGA") || sData.Contains("$GPGSA")) {
                            Console.WriteLine(" This is a GPS device!");
                            serial.Close();
                            return true;
                        }
                    }
                }
            });
            return result;
        }
        #endregion
    }
}