1 files changed, 91 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/ContentPresenter.cs b/Xamarin.Forms.Core/ContentPresenter.cs
new file mode 100644
index 00000000..a99a048b
--- /dev/null
+++ b/Xamarin.Forms.Core/ContentPresenter.cs
@@ -0,0 +1,91 @@
+using System;
+
+namespace Xamarin.Forms
+{
+	public class ContentPresenter : Layout
+	{
+		public static BindableProperty ContentProperty = BindableProperty.Create("Content", typeof(View), typeof(ContentPresenter), null, propertyChanged: OnContentChanged);
+
+		public ContentPresenter()
+		{
+			SetBinding(ContentProperty, new TemplateBinding("Content"));
+		}
+
+		public View Content
+		{
+			get { return (View)GetValue(ContentProperty); }
+			set { SetValue(ContentProperty, value); }
+		}
+
+		protected override void LayoutChildren(double x, double y, double width, double height)
+		{
+			for (var i = 0; i < LogicalChildren.Count; i++)
+			{
+				Element element = LogicalChildren[i];
+				var child = element as View;
+				if (child != null)
+					LayoutChildIntoBoundingRegion(child, new Rectangle(x, y, width, height));
+			}
+		}
+
+		[Obsolete("Use OnMeasure")]
+		protected override SizeRequest OnSizeRequest(double widthConstraint, double heightConstraint)
+		{
+			double widthRequest = WidthRequest;
+			double heightRequest = HeightRequest;
+			var childRequest = new SizeRequest();
+			if ((widthRequest == -1 || heightRequest == -1) && Content != null)
+			{
+				childRequest = Content.Measure(widthConstraint, heightConstraint, MeasureFlags.IncludeMargins);
+			}
+
+			return new SizeRequest
+			{
+				Request = new Size { Width = widthRequest != -1 ? widthRequest : childRequest.Request.Width, Height = heightRequest != -1 ? heightRequest : childRequest.Request.Height },
+				Minimum = childRequest.Minimum
+			};
+		}
+
+		internal virtual void Clear()
+		{
+			Content = null;
+		}
+
+		internal override void ComputeConstraintForView(View view)
+		{
+			bool isFixedHorizontally = (Constraint & LayoutConstraint.HorizontallyFixed) != 0;
+			bool isFixedVertically = (Constraint & LayoutConstraint.VerticallyFixed) != 0;
+
+			var result = LayoutConstraint.None;
+			if (isFixedVertically && view.VerticalOptions.Alignment == LayoutAlignment.Fill)
+				result |= LayoutConstraint.VerticallyFixed;
+			if (isFixedHorizontally && view.HorizontalOptions.Alignment == LayoutAlignment.Fill)
+				result |= LayoutConstraint.HorizontallyFixed;
+			view.ComputedConstraint = result;
+		}
+
+		internal override void SetChildInheritedBindingContext(Element child, object context)
+		{
+			// We never want to use the standard inheritance mechanism, we will get this set by our parent
+		}
+
+		static async void OnContentChanged(BindableObject bindable, object oldValue, object newValue)
+		{
+			var self = (ContentPresenter)bindable;
+
+			var oldView = (View)oldValue;
+			var newView = (View)newValue;
+			if (oldView != null)
+			{
+				self.InternalChildren.Remove(oldView);
+				oldView.ParentOverride = null;
+			}
+
+			if (newView != null)
+			{
+				self.InternalChildren.Add(newView);
+				newView.ParentOverride = await TemplateUtilities.FindTemplatedParentAsync((Element)bindable);
+			}
+		}
+	}
+}
+\ No newline at end of file