public class OrderViewModel : Notifier
    {
        DispatcherTimer dispatcherTimer = new DispatcherTimer();
        private SoftproofTransporterClientApi api = new SoftproofTransporterClientApi();
        private ObservableCollection<Order> _orders = new ObservableCollection<Order>();
        public ObservableCollection<Order> Orders
        {
            get { return _orders; }
            set { PropertySetter(ref _orders, "Orders", value); }
        }

        public OrderViewModel()
        {
            dispatcherTimer.Tick += new EventHandler(UpdateOrders);
            dispatcherTimer.Interval = new TimeSpan(0, 0, 2);
            dispatcherTimer.Start();
        }

        private void UpdateOrders(object sender, EventArgs e)
        {
            GetOrders();
        }

        private void GetOrders()
        {
            api.GetOrders((orderResult) =>
                Deployment.Current.Dispatcher.BeginInvoke( ()=>
                {
                    DateTime dt = DateTime.Now;
                    string time = String.Format("{0:d/M/yyyy HH:mm:ss}", dt);
                    try
                    {
                        Orders = orderResult.Orders;
                        Debug.WriteLine("Updated Orders at " + time);
                    }
                    catch { Debug.WriteLine("Could not get Orders at " + time); }
                })
           );
        }

    }