1 files changed, 114 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs b/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs
new file mode 100644
index 00000000..64b2daab
--- /dev/null
+++ b/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs
@@ -0,0 +1,114 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Media;
+using WBinding = Windows.UI.Xaml.Data.Binding;
+using WBindingExpression = Windows.UI.Xaml.Data.BindingExpression;
+
+#if WINDOWS_UWP
+
+namespace Xamarin.Forms.Platform.UWP
+#else
+
+namespace Xamarin.Forms.Platform.WinRT
+#endif
+{
+	internal static class FrameworkElementExtensions
+	{
+		static readonly Lazy<ConcurrentDictionary<Type, DependencyProperty>> ForegroundProperties =
+			new Lazy<ConcurrentDictionary<Type, DependencyProperty>>(() => new ConcurrentDictionary<Type, DependencyProperty>());
+
+		public static Brush GetForeground(this FrameworkElement element)
+		{
+			if (element == null)
+				throw new ArgumentNullException("element");
+
+			return (Brush)element.GetValue(GetForegroundProperty(element));
+		}
+
+		public static WBinding GetForegroundBinding(this FrameworkElement element)
+		{
+			WBindingExpression expr = element.GetBindingExpression(GetForegroundProperty(element));
+			if (expr == null)
+				return null;
+
+			return expr.ParentBinding;
+		}
+
+		public static object GetForegroundCache(this FrameworkElement element)
+		{
+			WBinding binding = GetForegroundBinding(element);
+			if (binding != null)
+				return binding;
+
+			return GetForeground(element);
+		}
+
+		public static void RestoreForegroundCache(this FrameworkElement element, object cache)
+		{
+			var binding = cache as WBinding;
+			if (binding != null)
+				SetForeground(element, binding);
+			else
+				SetForeground(element, (Brush)cache);
+		}
+
+		public static void SetForeground(this FrameworkElement element, Brush foregroundBrush)
+		{
+			if (element == null)
+				throw new ArgumentNullException("element");
+
+			element.SetValue(GetForegroundProperty(element), foregroundBrush);
+		}
+
+		public static void SetForeground(this FrameworkElement element, WBinding binding)
+		{
+			if (element == null)
+				throw new ArgumentNullException("element");
+
+			element.SetBinding(GetForegroundProperty(element), binding);
+		}
+
+		internal static T GetFirstDescendant<T>(this DependencyObject element) where T : FrameworkElement
+		{
+			int count = VisualTreeHelper.GetChildrenCount(element);
+			for (var i = 0; i < count; i++)
+			{
+				DependencyObject child = VisualTreeHelper.GetChild(element, i);
+
+				T target = child as T ?? GetFirstDescendant<T>(child);
+				if (target != null)
+					return target;
+			}
+
+			return null;
+		}
+
+		static DependencyProperty GetForegroundProperty(FrameworkElement element)
+		{
+			if (element is Control)
+				return Control.ForegroundProperty;
+			if (element is TextBlock)
+				return TextBlock.ForegroundProperty;
+
+			Type type = element.GetType();
+
+			DependencyProperty foregroundProperty;
+			if (!ForegroundProperties.Value.TryGetValue(type, out foregroundProperty))
+			{
+				FieldInfo field = type.GetFields().FirstOrDefault(f => f.Name == "ForegroundProperty");
+				if (field == null)
+					throw new ArgumentException("type is not a Foregroundable type");
+
+				var property = (DependencyProperty)field.GetValue(null);
+				ForegroundProperties.Value.TryAdd(type, property);
+
+				return property;
+			}
+
+			return foregroundProperty;
+		}
+	}
+}
+\ No newline at end of file