XAML-Map-Control/MapControl/Shared/MapMultiPolygon.cs

using System.Collections.Generic;
#if WPF
using System.Windows;
#elif UWP
using Windows.UI.Xaml;
#elif WINUI
using Microsoft.UI.Xaml;
#endif

namespace MapControl
{
    /// <summary>
    /// A multi-polygon defined by a collection of collections of Locations.
    /// Allows to draw filled polygons with holes.
    /// 
    /// A PolygonCollection (with ObservableCollection of Location elements) may be used
    /// for the Polygons property if collection changes of the property itself and its
    /// elements are both supposed to trigger UI updates.
    /// </summary>
    public partial class MapMultiPolygon : MapPolypoint
    {
        public static readonly DependencyProperty PolygonsProperty =
            DependencyPropertyHelper.Register<MapMultiPolygon, IEnumerable<IEnumerable<Location>>>(nameof(Polygons), null,
                (polygon, oldValue, newValue) => polygon.DataCollectionPropertyChanged(oldValue, newValue));

        /// <summary>
        /// Gets or sets the Locations that define the multi-polygon points.
        /// </summary>
        public IEnumerable<IEnumerable<Location>> Polygons
        {
            get => (IEnumerable<IEnumerable<Location>>)GetValue(PolygonsProperty);
            set => SetValue(PolygonsProperty, value);
        }

        protected override void UpdateData()
        {
            UpdateData(Polygons);
        }
    }
}