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-rw-r--r--Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs114
1 files changed, 114 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs b/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs
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+++ b/Xamarin.Forms.Platform.WinRT/FrameworkElementExtensions.cs
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+´╗┐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