How To implement Move to Region in xamarin forms google map MVVM

I want to Update map position and move to region when user select specific city
I do that but no thing changed

this is my code

Location.xaml.cs

 public partial class LocationPage : ContentPage
    {
        public static BindableMap StoresMap;

        public LocationPage()
        {
            StoresMap = LocationMap;
            InitializeComponent();
        }
}

Note : BindableMap is Custom Render form Map and i Used Google Map for this

and in view model

                             MabPosition = new Position(24.774265, 46.738586);
                             var Loc = StoresAddresses.FirstOrDefault();
                             LocationPage.StoresMap.MoveToRegion(new MapSpan(MabPosition, 24.774265, 46.738586));

what's the problem ?