Added PropertyHelper

MapControl/Shared/MapOverlay.cs

@@ -4,12 +4,9 @@
 
 #if WINDOWS_UWP
 using Windows.UI.Text;
-using Windows.UI.Xaml;
-using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 #else
 using System.Windows;
-using System.Windows.Data;
 using System.Windows.Media;
 #endif
 
@@ -109,10 +106,5 @@ namespace MapControl
             get { return (double)GetValue(StrokeMiterLimitProperty); }
             set { SetValue(StrokeMiterLimitProperty, value); }
         }
-
-        protected Binding GetBinding(string propertyName)
-        {
-            return new Binding { Source = this, Path = new PropertyPath(propertyName) };
-        }
     }
 }

MapControl/Shared/MapScale.cs

@@ -39,10 +39,10 @@ namespace MapControl
         {
             MinWidth = 100d;
 
-            line.SetBinding(Shape.StrokeProperty, GetBinding(nameof(Stroke)));
+            line.SetBinding(Shape.StrokeProperty, this.GetBinding(nameof(Stroke)));
-            line.SetBinding(Shape.StrokeThicknessProperty, GetBinding(nameof(StrokeThickness)));
+            line.SetBinding(Shape.StrokeThicknessProperty, this.GetBinding(nameof(StrokeThickness)));
 #if WINDOWS_UWP
-            label.SetBinding(TextBlock.ForegroundProperty, GetBinding(nameof(Foreground)));
+            label.SetBinding(TextBlock.ForegroundProperty, this.GetBinding(nameof(Foreground)));
 #endif
             Children.Add(line);
             Children.Add(label);

MapControl/Shared/PropertyHelper.cs

@@ -0,0 +1,32 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2021 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+#if WINDOWS_UWP
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Data;
+#else
+using System.Windows;
+using System.Windows.Data;
+#endif
+
+namespace MapControl
+{
+    public static class PropertyHelper
+    {
+        public static Binding GetBinding(this object sourceObject, string sourceProperty)
+        {
+            return new Binding { Source = sourceObject, Path = new PropertyPath(sourceProperty) };
+        }
+
+        public static void ValidateProperty(
+            this FrameworkElement targetObject, DependencyProperty targetProperty, object sourceObject, string sourceProperty)
+        {
+            if (targetObject.GetValue(targetProperty) == null &&
+                targetObject.GetBindingExpression(targetProperty) == null)
+            {
+                targetObject.SetBinding(targetProperty, sourceObject.GetBinding(sourceProperty));
+            }
+        }
+    }
+}

MapControl/UWP/MapContentControl.UWP.cs

@@ -4,7 +4,6 @@
 
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
-using Windows.UI.Xaml.Data;
 
 namespace MapControl
 {
@@ -49,24 +48,13 @@ namespace MapControl
         {
             base.OnApplyTemplate();
 
-            var map = MapPanel.GetParentMap(this);
+            var parentMap = MapPanel.GetParentMap(this);
 
-            if (map != null)
+            if (parentMap != null)
             {
-                if (Background == null)
+                this.ValidateProperty(BackgroundProperty, parentMap, nameof(MapBase.Background));
-                {
+                this.ValidateProperty(BorderBrushProperty, parentMap, nameof(MapBase.Foreground));
-                    SetBinding(BackgroundProperty, new Binding { Source = map, Path = new PropertyPath(nameof(MapBase.Background)) });
+                this.ValidateProperty(ForegroundProperty, parentMap, nameof(MapBase.Foreground));
-                }
-
-                if (BorderBrush == null)
-                {
-                    SetBinding(BorderBrushProperty, new Binding { Source = map, Path = new PropertyPath(nameof(MapBase.Foreground)) });
-                }
-
-                if (Foreground == null)
-                {
-                    SetBinding(ForegroundProperty, new Binding { Source = map, Path = new PropertyPath(nameof(MapBase.Foreground)) });
-                }
             }
         }
     }

MapControl/UWP/MapControl.UWP.csproj

@@ -131,6 +131,9 @@
     <Compile Include="..\Shared\OrthographicProjection.cs">
       <Link>OrthographicProjection.cs</Link>
     </Compile>
+    <Compile Include="..\Shared\PropertyHelper.cs">
+      <Link>PropertyHelper.cs</Link>
+    </Compile>
     <Compile Include="..\Shared\StereographicProjection.cs">
       <Link>StereographicProjection.cs</Link>
     </Compile>

MapControl/UWP/MapGraticule.UWP.cs

@@ -29,11 +29,11 @@ namespace MapControl
                 if (path == null)
                 {
                     path = new Path { Data = new PathGeometry() };
-                    path.SetBinding(Shape.StrokeProperty, GetBinding(nameof(Stroke)));
+                    path.SetBinding(Shape.StrokeProperty, this.GetBinding(nameof(Stroke)));
-                    path.SetBinding(Shape.StrokeThicknessProperty, GetBinding(nameof(StrokeThickness)));
+                    path.SetBinding(Shape.StrokeThicknessProperty, this.GetBinding(nameof(StrokeThickness)));
-                    path.SetBinding(Shape.StrokeDashArrayProperty, GetBinding(nameof(StrokeDashArray)));
+                    path.SetBinding(Shape.StrokeDashArrayProperty, this.GetBinding(nameof(StrokeDashArray)));
-                    path.SetBinding(Shape.StrokeDashOffsetProperty, GetBinding(nameof(StrokeDashOffset)));
+                    path.SetBinding(Shape.StrokeDashOffsetProperty, this.GetBinding(nameof(StrokeDashOffset)));
-                    path.SetBinding(Shape.StrokeDashCapProperty, GetBinding(nameof(StrokeDashCap)));
+                    path.SetBinding(Shape.StrokeDashCapProperty, this.GetBinding(nameof(StrokeDashCap)));
                     Children.Add(path);
                 }
 
@@ -109,15 +109,15 @@ namespace MapControl
                         else
                         {
                             label = new TextBlock { RenderTransform = new MatrixTransform() };
-                            label.SetBinding(TextBlock.FontSizeProperty, GetBinding(nameof(FontSize)));
+                            label.SetBinding(TextBlock.FontSizeProperty, this.GetBinding(nameof(FontSize)));
-                            label.SetBinding(TextBlock.FontStyleProperty, GetBinding(nameof(FontStyle)));
+                            label.SetBinding(TextBlock.FontStyleProperty, this.GetBinding(nameof(FontStyle)));
-                            label.SetBinding(TextBlock.FontStretchProperty, GetBinding(nameof(FontStretch)));
+                            label.SetBinding(TextBlock.FontStretchProperty, this.GetBinding(nameof(FontStretch)));
-                            label.SetBinding(TextBlock.FontWeightProperty, GetBinding(nameof(FontWeight)));
+                            label.SetBinding(TextBlock.FontWeightProperty, this.GetBinding(nameof(FontWeight)));
-                            label.SetBinding(TextBlock.ForegroundProperty, GetBinding(nameof(Foreground)));
+                            label.SetBinding(TextBlock.ForegroundProperty, this.GetBinding(nameof(Foreground)));
 
                             if (FontFamily != null)
                             {
-                                label.SetBinding(TextBlock.FontFamilyProperty, GetBinding(nameof(FontFamily)));
+                                label.SetBinding(TextBlock.FontFamilyProperty, this.GetBinding(nameof(FontFamily)));
                             }
 
                             Children.Add(label);

MapControl/UWP/MapItemsControl.UWP.cs

@@ -30,6 +30,20 @@ namespace MapControl
             (ItemsControl.ItemsControlFromItemContainer(this) as MapItemsControl)?.OnItemClicked(
                 this, e.KeyModifiers.HasFlag(VirtualKeyModifiers.Control), e.KeyModifiers.HasFlag(VirtualKeyModifiers.Shift));
         }
+
+        protected override void OnApplyTemplate()
+        {
+            base.OnApplyTemplate();
+
+            var parentMap = MapPanel.GetParentMap(this);
+
+            if (parentMap != null)
+            {
+                this.ValidateProperty(BackgroundProperty, parentMap, nameof(MapBase.Background));
+                this.ValidateProperty(BorderBrushProperty, parentMap, nameof(MapBase.Foreground));
+                this.ValidateProperty(ForegroundProperty, parentMap, nameof(MapBase.Foreground));
+            }
+        }
     }
 
     public partial class MapItemsControl

MapControl/UWP/MapOverlay.UWP.cs

@@ -4,7 +4,6 @@
 
 using Windows.UI.Text;
 using Windows.UI.Xaml;
-using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
 namespace MapControl
@@ -65,15 +64,8 @@ namespace MapControl
         {
             if (map != null)
             {
-                if (Foreground == null)
+                this.ValidateProperty(ForegroundProperty, map, nameof(MapBase.Foreground));
-                {
+                this.ValidateProperty(StrokeProperty, this, nameof(Foreground));
-                    SetBinding(ForegroundProperty, new Binding { Source = map, Path = new PropertyPath(nameof(MapBase.Foreground)) });
-                }
-
-                if (Stroke == null)
-                {
-                    SetBinding(StrokeProperty, GetBinding(nameof(Foreground)));
-                }
             }
 
             base.SetParentMap(map);

MapControl/UWP/Themes/Generic.xaml

@@ -49,7 +49,6 @@
     <Style TargetType="map:Pushpin" BasedOn="{StaticResource ContentControlStyle}">
         <Setter Property="HorizontalAlignment" Value="Left"/>
         <Setter Property="VerticalAlignment" Value="Bottom"/>
-        <Setter Property="UseLayoutRounding" Value="True"/>
         <Setter Property="Padding" Value="5,3"/>
         <Setter Property="Template">
             <Setter.Value>

MapControl/WPF/MapOverlay.WPF.cs

@@ -65,11 +65,7 @@ namespace MapControl
         protected override void OnInitialized(EventArgs e)
         {
             base.OnInitialized(e);
-
+            this.ValidateProperty(StrokeProperty, this, nameof(Foreground));
-            if (Stroke == null)
-            {
-                SetBinding(StrokeProperty, GetBinding(nameof(Foreground)));
-            }
         }
 
         public Pen CreatePen()

SampleApps/UniversalApp/MainPage.xaml

@@ -23,7 +23,6 @@
         <Style x:Key="PointItemStyle" TargetType="map:MapItem">
             <Setter Property="AutoCollapse" Value="True"/>
             <Setter Property="LocationMemberPath" Value="Location"/>
-            <Setter Property="Foreground" Value="Gray"/>
             <Setter Property="FontSize" Value="12"/>
             <Setter Property="Template">
                 <Setter.Value>