Code.cs

namespace App
{
    public partial class ExtendedMap : Map
    {
        public static readonly BindableProperty TappedCommandProperty =
       BindableProperty.Create(nameof(TappedCommand), typeof(DelegateCommand<object>), typeof(ExtendedMap), default(DelegateCommand<object>));

        public DelegateCommand<object> TappedCommand
        {
            get { return (DelegateCommand<object>)GetValue(TappedCommandProperty); }
            set { SetValue(TappedCommandProperty, value); }
        }

        public ExtendedMap()
        {
            InitializeComponent();
        }

        protected override void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            base.OnPropertyChanged(propertyName);

            if (propertyName == Map.ItemsSourceProperty.PropertyName)
            {
                var pin = ItemsSource.FirstOrNull();
                if (pin is MapPin mapPin)
                {
                    MapSpan mapSpan = MapSpan.FromCenterAndRadius(mapPin.Position, Distance.FromKilometers(0.444));
                    MoveToRegion(mapSpan);
                }
            }
        }

        void Map_MapClicked(System.Object sender, Xamarin.Forms.Maps.MapClickedEventArgs e)
        {
            if (TappedCommand != null)
            {
                TappedCommand?.Execute(e.Position);
            }
        }
    }
}