MapMultiPolygon

MapControl/Shared/MapMultiPolygon.cs

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+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// Copyright © 2024 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+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 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);
+        }
+    }
+}

MapControl/Shared/PolygonCollection.cs

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+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// Copyright © 2024 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.Linq;
+
+namespace MapControl
+{
+    /// <summary>
+    /// An ObservableCollection of IEnumerable of Location. PolygonCollection adds a CollectionChanged
+    /// listener to each element that implements INotifyCollectionChanged and, when such an element changes,
+    /// fires its own CollectionChanged event with NotifyCollectionChangedAction.Replace for that element.
+    /// </summary>
+    public class PolygonCollection : ObservableCollection<IEnumerable<Location>>
+    {
+        private void PolygonChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, sender, sender));
+        }
+
+        protected override void InsertItem(int index, IEnumerable<Location> polygon)
+        {
+            if (polygon is INotifyCollectionChanged addedPolygon)
+            {
+                addedPolygon.CollectionChanged += PolygonChanged;
+            }
+
+            base.InsertItem(index, polygon);
+        }
+
+        protected override void SetItem(int index, IEnumerable<Location> polygon)
+        {
+            if (this[index] is INotifyCollectionChanged removedPolygon)
+            {
+                removedPolygon.CollectionChanged -= PolygonChanged;
+            }
+
+            if (polygon is INotifyCollectionChanged addedPolygon)
+            {
+                addedPolygon.CollectionChanged += PolygonChanged;
+            }
+
+            base.SetItem(index, polygon);
+        }
+
+        protected override void RemoveItem(int index)
+        {
+            if (this[index] is INotifyCollectionChanged removedPolygon)
+            {
+                removedPolygon.CollectionChanged -= PolygonChanged;
+            }
+
+            base.RemoveItem(index);
+        }
+
+        protected override void ClearItems()
+        {
+            foreach (var polygon in this.OfType<INotifyCollectionChanged>())
+            {
+                polygon.CollectionChanged -= PolygonChanged;
+            }
+
+            base.ClearItems();
+        }
+    }
+}