为什么地图在同一地点开放？ Xamarin.Forms（）

Question

我正在开发一个应该在android或ios上打开地图的应用程序。我面临的问题（在Android上，IOS仍未测试）是它打开地图，总是在同一位置，似乎是我的位置，而不是定义的位置。这是我的代码......

public MainPage()
    {
        InitializeComponent();
        storesList.BackgroundColor = Color.CornflowerBlue;
        storesList.SeparatorColor=Color.White;
        storesList.ItemSelected += CellSelected;
        storesList.ItemTemplate = new DataTemplate(() =>
        {
            var storeCell = new StoreCell();
            storeCell.SetBinding(StoreCell.NameProperty, "Name");
            storeCell.SetBinding(StoreCell.LocationProperty, "Location");
            storeCell.SetBinding(StoreCell.ScheduleProperty, "Schedule");

            return storeCell;
        });

        Stores = new ObservableCollection<Store>();

        Store store1 = new Store
        {
            Name = "Pombal",
            Location = new Coordinate(39.9143958, -8.6297282).ToString()
        };
        Store store2 = new Store
        {
            Name = "Unknown",
            Location = new Coordinate(39.7301803, -8.8438668).ToString(),
            Schedule = "09:00-12:30 / 13:30-18:00"
        };

        Stores.Add(store1);
        Stores.Add(store2);
        Stores.Add(store1);
        Stores.Add(store2);
        Stores.Add(store1);
        Stores.Add(store2);
        Stores.Add(store1);
        Stores.Add(store2);
        storesList.ItemsSource = Stores;

    }

    void CellSelected(object sender, SelectedItemChangedEventArgs e)
    {
        var address = ((Store)e.SelectedItem).Location.Replace(" ", "");
        //storesList.SelectedItem = null;

        Uri uri;
        switch (Device.RuntimePlatform)
        {
            case Device.iOS:
                 uri = new Uri(string.Format("http://maps.apple.com/?q={0}", address));
                System.Diagnostics.Debug.WriteLine(uri);
                Device.OpenUri(uri);
            break;

            case Device.Android:
                uri = new Uri("geo:" + address);
                System.Diagnostics.Debug.WriteLine(uri);
                Device.OpenUri(uri);
            break;
        }
    }

此外，如果你可以帮我，列表的项目不是取消选择我在哪里放置这个storesList.SelectedItem = null;，以便当我回到我的应用程序时，我可以选择与我之前相同的项目（它不工作我拥有它，我得到空引用异常）