1 files changed, 74 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs
new file mode 100644
index 00000000..0e669774
--- /dev/null
+++ b/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs
@@ -0,0 +1,74 @@
+using Windows.UI.Xaml;
+
+#if WINDOWS_UWP
+
+namespace Xamarin.Forms.Platform.UWP
+#else
+
+namespace Xamarin.Forms.Platform.WinRT
+#endif
+{
+	public class NativeViewWrapperRenderer : ViewRenderer<NativeViewWrapper, FrameworkElement>
+	{
+		public override SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
+		{
+			if (Element?.GetDesiredSizeDelegate == null)
+			{
+				return base.GetDesiredSize(widthConstraint, heightConstraint);
+			}
+
+			// The user has specified a different implementation of GetDesiredSize
+			SizeRequest? result = Element.GetDesiredSizeDelegate(this, widthConstraint, heightConstraint);
+
+			// If the delegate returns a SizeRequest, we use it; 
+			// if it returns null, fall back to the default implementation
+			return result ?? base.GetDesiredSize(widthConstraint, heightConstraint);
+		}
+
+		protected override Windows.Foundation.Size ArrangeOverride(Windows.Foundation.Size finalSize)
+		{
+			if (Element?.ArrangeOverrideDelegate == null)
+			{
+				return base.ArrangeOverride(finalSize);
+			}
+
+			// The user has specified a different implementation of ArrangeOverride
+			Windows.Foundation.Size? result = Element.ArrangeOverrideDelegate(this, finalSize);
+
+			// If the delegate returns a Size, we use it; 
+			// if it returns null, fall back to the default implementation
+			return result ?? base.ArrangeOverride(finalSize);
+		}
+
+		protected Windows.Foundation.Size MeasureOverride()
+		{
+			return MeasureOverride(new Windows.Foundation.Size());
+		}
+
+		protected override Windows.Foundation.Size MeasureOverride(Windows.Foundation.Size availableSize)
+		{
+			if (Element?.MeasureOverrideDelegate == null)
+			{
+				return base.MeasureOverride(availableSize);
+			}
+
+			// The user has specified a different implementation of MeasureOverride
+			Windows.Foundation.Size? result = Element.MeasureOverrideDelegate(this, availableSize);
+
+			// If the delegate returns a Size, we use it; 
+			// if it returns null, fall back to the default implementation
+			return result ?? base.MeasureOverride(availableSize);
+		}
+
+		protected override void OnElementChanged(ElementChangedEventArgs<NativeViewWrapper> e)
+		{
+			base.OnElementChanged(e);
+
+			if (e.OldElement == null)
+			{
+				SetNativeControl(Element.NativeElement);
+				Control.LayoutUpdated += (sender, args) => { Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); };
+			}
+		}
+	}
+}
+\ No newline at end of file