protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            var viewModel = new CarViewModel();
            await viewModel.InitializeData();

            this.DataContext = viewModel;


            MapLayer layer = new MapLayer();
            var      pts   = new List <GeoCoordinate>();

            foreach (var item in viewModel.Cars)
            {
                Pushpin pushpin = new Pushpin();
                pushpin.GeoCoordinate = new System.Device.Location.GeoCoordinate(item.latitude, item.longitude);


                MapOverlay overlay = new MapOverlay();
                overlay.Content       = pushpin;
                overlay.GeoCoordinate = new System.Device.Location.GeoCoordinate(item.latitude, item.longitude);
                layer.Add(overlay);

                pts.Add(new System.Device.Location.GeoCoordinate(item.latitude, item.longitude));
            }

            map.Layers.Clear();
            map.Layers.Add(layer);

            map.SetView(LocationRectangle.CreateBoundingRectangle(pts));

            base.OnNavigatedTo(e);
        }