trying to get changes in source to reflect in UI (WPF DATAGRID)

 public class CompressorEngine : ObservableCollection <power>
    {
        public static ArrayList GetCompressor()
        {
            MySqlConnection conn = new MySqlConnection(" ");
            conn.Open();
            MySqlCommand comm = conn.CreateCommand();
            comm.CommandText = "SELECT ABIUnits.UnitSerialNumber, Region, AssetDescription, Location_Latitude, Location_Longitude, Street, City, ABIUnits_Alerts.Time, ABIUnits_Alerts.Comment, Alert_Type, Alert_ID FROM ABIUnits JOIN ABIUnits_Alerts ON ABIUnits.UnitSerialNumber = ABIUnits_Alerts.UnitSerialNumber WHERE ABIUnits_Alerts.Checked = '" + 0 + "' AND ABIUnits_Alerts.AlertGroup = '" + 3 + "' ORDER BY ABIUnits_Alerts.Time Desc";
           
            MySqlDataReader reader = comm.ExecuteReader();
            string alert_id;
            string unitserialnumber;
            string alerttype;
            string time1;
            string assetdescription;
            string region;
            string location_latitude;
            string location_longitude;
            string street;
            string city;
            ArrayList plist = new ArrayList();
            Compressor titlepower = new Compressor("Alert ID", "Unit Serial Number", "Alert", "Time", "Description", "Latitude", "Longitude", "Region", "Street", "City");
            plist.Add(titlepower);
            while (reader.Read())
            {
                alert_id = reader["ALert_ID"].ToString();
                unitserialnumber = reader["UnitSerialNumber"].ToString();
                alerttype = reader["ALert_Type"].ToString();
                time1 = reader["Time"].ToString();
                assetdescription = reader["AssetDescription"].ToString();
                region = reader["Region"].ToString();
                location_latitude = reader["Location_Latitude"].ToString();
                location_longitude = reader["Location_Longitude"].ToString();
                street = reader["Street"].ToString();
                city = reader["City"].ToString();
                Compressor compressor = new Compressor(alert_id, unitserialnumber, alerttype, time1, assetdescription, location_latitude, location_longitude, region, street, city);
                plist.Add(compressor);

            }
            conn.Close();
            return plist;
        }
    }
    public class Compressor : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged(string info)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(info));
            }

        }
        private string _p_id;
        private string _units;
        private string _alert;
        private string _time;
        private string _assetdescription1;
        private string _location_latitude1;
        private string _location_longitude1;
        private string _region1;
        private string _street1;
        private string _city1;

        public Compressor(string p_id, string units, string alert, string time, string assetdescription1, string location_latitude1, string location_longitude1, string region1, string street1, string city1)
        {
            _p_id = p_id;
            _units = units;
            _alert = alert;
            _time = time;
            _assetdescription1 = assetdescription1;
            _location_latitude1 = location_latitude1;
            _location_longitude1 = location_longitude1;
            _region1 = region1;
            _city1 = city1;
            _street1 = street1;

        }


        public string P_id
        {
            get { return _p_id; }
            set { _p_id = value; OnPropertyChanged("P_id"); }

        }
        public string Units
        {
            get { return _units; }
            set { _units = value; OnPropertyChanged("Units"); }
        }
        public string Alert
        {
            get { return _alert; }
            set { _alert = value; OnPropertyChanged("Alert"); }
        }

        public string Time
        {
            get { return _time; }
            set { _time = value; OnPropertyChanged("Time"); }
        }
        public string AssetDescription1
        {
            get { return _assetdescription1; }
            set { _assetdescription1 = value; OnPropertyChanged("AssetDescription1"); }
        }
        public string Location_Latitude1
        {
            get { return _location_latitude1; }
            set { _location_latitude1 = value; OnPropertyChanged("Location_Latitude1"); }
        }
        public string Location_Longitude1
        {
            get { return _location_longitude1; }
            set { _location_longitude1 = value; OnPropertyChanged("Location_Longitude1"); }
        }
        public string Region1
        {
            get { return _region1; }
            set { _region1 = value; OnPropertyChanged("Region1"); }
        }
        public string Street1
        {
            get { return _street1; }
            set { _street1 = value; OnPropertyChanged("Street1"); }
        }
        public string City1
        {
            get { return _city1; }
            set { _city1 = value; OnPropertyChanged("City1"); }
        }
    }
</power>