Added MapBase.MapLayerItemsSource property

MapControl/Shared/MapBase.MapLayer.cs

@@ -0,0 +1,241 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.Linq;
+#if WPF
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Threading;
+#elif UWP
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Media;
+#elif WINUI
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Media;
+#endif
+
+namespace MapControl
+{
+    public interface IMapLayer : IMapElement
+    {
+        Brush MapBackground { get; }
+        Brush MapForeground { get; }
+    }
+
+    public partial class MapBase
+    {
+        public static readonly DependencyProperty MapLayerProperty =
+            DependencyPropertyHelper.Register<MapBase, FrameworkElement>(nameof(MapLayer), null,
+                (map, oldValue, newValue) => map.MapLayerPropertyChanged(oldValue, newValue));
+
+        public static readonly DependencyProperty MapLayerItemsSourceProperty =
+            DependencyPropertyHelper.Register<MapBase, IEnumerable>(nameof(MapLayerItemsSource), null,
+                (map, oldValue, newValue) => map.MapLayerItemsSourcePropertyChanged(oldValue, newValue));
+
+        /// <summary>
+        /// Gets or sets the base map layer, which is added as first element to the Children collection.
+        /// If the layer implements IMapLayer (like MapTileLayer or MapImageLayer), its (non-null) MapBackground
+        /// and MapForeground property values are used for the MapBase Background and Foreground properties.
+        /// </summary>
+        public FrameworkElement MapLayer
+        {
+            get => (FrameworkElement)GetValue(MapLayerProperty);
+            set => SetValue(MapLayerProperty, value);
+        }
+
+        public IEnumerable MapLayerItemsSource
+        {
+            get => (IEnumerable)GetValue(MapLayerItemsSourceProperty);
+            set => SetValue(MapLayerItemsSourceProperty, value);
+        }
+
+        private void MapLayerPropertyChanged(FrameworkElement oldLayer, FrameworkElement newLayer)
+        {
+            if (oldLayer != null)
+            {
+                if (Children.Count > 0 && Children[0] == oldLayer)
+                {
+                    Children.RemoveAt(0);
+                }
+
+                if (oldLayer is IMapLayer mapLayer)
+                {
+                    if (mapLayer.MapBackground != null)
+                    {
+                        ClearValue(BackgroundProperty);
+                    }
+                    if (mapLayer.MapForeground != null)
+                    {
+                        ClearValue(ForegroundProperty);
+                    }
+                }
+            }
+
+            if (newLayer != null)
+            {
+                if (Children.Count == 0 || Children[0] != newLayer)
+                {
+                    Children.Insert(0, newLayer);
+                }
+
+                if (newLayer is IMapLayer mapLayer)
+                {
+                    if (mapLayer.MapBackground != null)
+                    {
+                        Background = mapLayer.MapBackground;
+                    }
+                    if (mapLayer.MapForeground != null)
+                    {
+                        Foreground = mapLayer.MapForeground;
+                    }
+                }
+            }
+        }
+
+        private void MapLayerItemsSourcePropertyChanged(IEnumerable oldItems, IEnumerable newItems)
+        {
+            if (oldItems != null)
+            {
+                if (oldItems is INotifyCollectionChanged incc)
+                {
+                    incc.CollectionChanged -= MapLayerItemsSourceCollectionChanged;
+                }
+
+                RemoveMapLayers(oldItems, 0);
+            }
+
+            if (newItems != null)
+            {
+                if (newItems is INotifyCollectionChanged incc)
+                {
+                    incc.CollectionChanged += MapLayerItemsSourceCollectionChanged;
+                }
+
+                AddMapLayers(newItems, 0);
+            }
+        }
+
+        private void MapLayerItemsSourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Add:
+                    AddMapLayers(e.NewItems, e.NewStartingIndex);
+                    break;
+
+                case NotifyCollectionChangedAction.Remove:
+                    RemoveMapLayers(e.OldItems, e.OldStartingIndex);
+                    break;
+
+                case NotifyCollectionChangedAction.Replace:
+                    RemoveMapLayers(e.OldItems, e.OldStartingIndex);
+                    AddMapLayers(e.NewItems, e.NewStartingIndex);
+                    break;
+
+                case NotifyCollectionChangedAction.Reset:
+                    break;
+
+                default:
+                    break;
+            }
+        }
+
+        private void AddMapLayers(IEnumerable items, int index)
+        {
+            var mapLayers = items.Cast<object>().Select(CreateMapLayer).ToList();
+#if WPF
+            // Execute at DispatcherPriority.DataBind to ensure that all bindings are evaluated.
+            Dispatcher.Invoke(() => AddMapLayers(mapLayers, index), DispatcherPriority.DataBind);
+#else
+            AddMapLayers(mapLayers, index);
+#endif
+        }
+
+        private void AddMapLayers(IEnumerable<FrameworkElement> mapLayers, int index)
+        {
+            foreach (var mapLayer in mapLayers)
+            {
+                Children.Insert(index, mapLayer);
+
+                if (index++ == 0)
+                {
+                    MapLayer = mapLayer;
+                }
+            }
+        }
+
+        private void RemoveMapLayers(IEnumerable items, int index)
+        {
+            Children.RemoveRange(index, items.Cast<object>().Count());
+
+            if (index == 0)
+            {
+                MapLayer = null;
+            }
+        }
+
+        private FrameworkElement CreateMapLayer(object item)
+        {
+            FrameworkElement mapLayer = null;
+
+            if (item != null)
+            {
+                mapLayer = item as FrameworkElement ?? TryLoadDataTemplate(item);
+            }
+
+            return mapLayer ?? new MapControl.MapPanel();
+        }
+
+        private FrameworkElement TryLoadDataTemplate(object item)
+        {
+            FrameworkElement element = null;
+#if AVALONIA
+            if (this.TryFindResource(item.GetType().FullName, out object value) &&
+                value is Avalonia.Markup.Xaml.Templates.DataTemplate template)
+            {
+                element = template.Build(item);
+            }
+#elif WPF
+            if (TryFindResource(new DataTemplateKey(item.GetType())) is DataTemplate template)
+            {
+                element = (FrameworkElement)template.LoadContent();
+            }
+#else
+            if (this.TryFindResource(item.GetType().FullName) is DataTemplate template)
+            {
+                element = (FrameworkElement)template.LoadContent();
+            }
+#endif
+            if (element != null)
+            {
+                element.DataContext = item;
+            }
+
+            return element;
+        }
+    }
+
+#if UWP || WINUI
+    internal static class MapBaseExtensions
+    {
+        public static void RemoveRange(this UIElementCollection elements, int index, int count)
+        {
+            while (--count >= 0)
+            {
+                elements.RemoveAt(index);
+            }
+        }
+
+        public static object TryFindResource(this FrameworkElement element, object key)
+        {
+            return element.Resources.ContainsKey(key)
+                ? element.Resources[key]
+                : element.Parent is FrameworkElement parent
+                ? TryFindResource(parent, key)
+                : null;
+        }
+    }
+#endif
+}

MapControl/Shared/MapBase.cs

@@ -12,12 +12,6 @@ using Microsoft.UI.Xaml.Media;
 
 namespace MapControl
 {
-    public interface IMapLayer : IMapElement
-    {
-        Brush MapBackground { get; }
-        Brush MapForeground { get; }
-    }
-
     /// <summary>
     /// The map control. Displays map content provided by one or more tile or image layers,
     /// such as MapTileLayerBase or MapImageLayer instances.
@@ -42,10 +36,6 @@ namespace MapControl
         public static readonly DependencyProperty AnimationDurationProperty =
             DependencyPropertyHelper.Register<MapBase, TimeSpan>(nameof(AnimationDuration), TimeSpan.FromSeconds(0.3));
 
-        public static readonly DependencyProperty MapLayerProperty =
-            DependencyPropertyHelper.Register<MapBase, FrameworkElement>(nameof(MapLayer), null,
-                (map, oldValue, newValue) => map.MapLayerPropertyChanged(oldValue, newValue));
-
         public static readonly DependencyProperty MapProjectionProperty =
             DependencyPropertyHelper.Register<MapBase, MapProjection>(nameof(MapProjection), new WebMercatorProjection(),
                 (map, oldValue, newValue) => map.MapProjectionPropertyChanged(newValue));
@@ -84,17 +74,6 @@ namespace MapControl
             set => SetValue(AnimationDurationProperty, value);
         }
 
-        /// <summary>
-        /// Gets or sets the base map layer, which is added as first element to the Children collection.
-        /// If the layer implements IMapLayer (like MapTileLayer or MapImageLayer), its (non-null) MapBackground
-        /// and MapForeground property values are used for the MapBase Background and Foreground properties.
-        /// </summary>
-        public FrameworkElement MapLayer
-        {
-            get => (FrameworkElement)GetValue(MapLayerProperty);
-            set => SetValue(MapLayerProperty, value);
-        }
-
         /// <summary>
         /// Gets or sets the MapProjection used by the map control.
         /// </summary>
@@ -440,49 +419,6 @@ namespace MapControl
             internalPropertyChange = false;
         }
 
-        private void MapLayerPropertyChanged(FrameworkElement oldLayer, FrameworkElement newLayer)
-        {
-            if (oldLayer != null)
-            {
-                if (Children.Count > 0 && Children[0] == oldLayer)
-                {
-                    Children.RemoveAt(0);
-                }
-
-                if (oldLayer is IMapLayer mapLayer)
-                {
-                    if (mapLayer.MapBackground != null)
-                    {
-                        ClearValue(BackgroundProperty);
-                    }
-                    if (mapLayer.MapForeground != null)
-                    {
-                        ClearValue(ForegroundProperty);
-                    }
-                }
-            }
-
-            if (newLayer != null)
-            {
-                if (Children.Count == 0 || Children[0] != newLayer)
-                {
-                    Children.Insert(0, newLayer);
-                }
-
-                if (newLayer is IMapLayer mapLayer)
-                {
-                    if (mapLayer.MapBackground != null)
-                    {
-                        Background = mapLayer.MapBackground;
-                    }
-                    if (mapLayer.MapForeground != null)
-                    {
-                        Foreground = mapLayer.MapForeground;
-                    }
-                }
-            }
-        }
-
         private void MapProjectionPropertyChanged(MapProjection projection)
         {
             maxLatitude = 90d;

MapControl/Shared/MapPanel.cs

@@ -41,8 +41,11 @@ namespace MapControl
                     {
                         mapElement.ParentMap = newValue;
                     }
-                },
-                true); // inherits
+#if UWP || WINUI
+                });
+#else
+                }, true); // inherits
+#endif
 
         public MapPanel()
         {