CarouselView Fixes (#101)

* Fix CarouselView.Item

* CarouselView formatting

* Move ItemsView.Count to IItemsViewController

* Remove dead code: CarouselView.IndexOf

* CarouselView re-layout subviews on resize.

* Add ItemTemplate to resources.xaml on UWP

* Docs

11 files changed, 104 insertions, 74 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/CarouselViewGallery.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/CarouselViewGallery.cs
index 9c7d9cd5..6288caa8 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/CarouselViewGallery.cs
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/CarouselViewGallery.cs
@@ -58,6 +58,7 @@ namespace Xamarin.Forms.Controls
 				return galleryPage;
 			}
 			public void Screenshot(string message) => _app.Screenshot(message);
+			public IApp App => _app;
 		}
 
 		public class CarouselViewGallery : IGalleryPage
@@ -256,22 +257,31 @@ namespace Xamarin.Forms.Controls
 				Assert.AreNotEqual(0, CarouselViewGallery.InitialItemId);
 				Assert.AreEqual(CarouselViewGallery.InitialItemId, carousel.ItemId);
 
-				// programatic jump to first/last
-				carousel.Last();
-				carousel.First();
+				gallery.App.SetOrientationPortrait();
 
-				// programatic step to page
-				carousel.StepToLast();
-				carousel.StepToFirst();
+				for (var i = 0; i < 2; i++)
+				{
+					// programatic jump to first/last
+					carousel.Last();
+					carousel.First();
+
+					// programatic step to page
+					carousel.StepToLast();
+					carousel.StepToFirst();
 
-				// swiping
-				carousel.SwipeToLast();
-				carousel.SwipeNext(); // test swipe past end
-				carousel.SwipeToFirst();
-				carousel.SwipePrevious(); // test swipe past start
+					// swiping
+					carousel.SwipeToLast();
+					carousel.SwipeNext(); // test swipe past end
+					carousel.SwipeToFirst();
+					carousel.SwipePrevious(); // test swipe past start
 
-			} catch (Exception e) {
-				gallery.Screenshot(e.ToString());
+					gallery.App.SetOrientationLandscape();
+				}
+
+				gallery.Screenshot("End");
+			}
+			catch (Exception e) {
+				gallery.Screenshot("End");
 				throw e;
 			}
 		}
diff --git a/Xamarin.Forms.Controls/GalleryPages/CarouselViewGallery.cs b/Xamarin.Forms.Controls/GalleryPages/CarouselViewGallery.cs
index c5b431d6..c2e0ef7f 100644
--- a/Xamarin.Forms.Controls/GalleryPages/CarouselViewGallery.cs
+++ b/Xamarin.Forms.Controls/GalleryPages/CarouselViewGallery.cs
@@ -246,14 +246,19 @@ namespace Xamarin.Forms.Controls
 			_eventLog = CreateValue(string.Empty, "EventLog");
 
 			_carouselView.ItemSelected += (s, o) => {
-				var selectedItem = ((Item)o.SelectedItem).Id;
-				_selectedItem.Text = $"{selectedItem}";
+				var selectedItem = (Item)o.SelectedItem;
+				var selectedItemId = selectedItem.Id;
+                if (selectedItem != _carouselView.Item)
+                    throw new Exception("CarouselView.Item != ItemSelected");
+				_selectedItem.Text = $"{selectedItemId}";
 				OnEvent("i");
 			};
 
 			_carouselView.PositionSelected += (s, o) => {
 				var selectedPosition = (int)o.SelectedPosition;
-				_selectedPosition.Text = $"{selectedPosition}";
+                if (_items[selectedPosition] != _carouselView.Item)
+                    throw new Exception("CarouselView.Item != Items[selectedPosition]");
+                _selectedPosition.Text = $"{selectedPosition}";
 				OnEvent("p");
 			};
 
diff --git a/Xamarin.Forms.Core/CarouselView.cs b/Xamarin.Forms.Core/CarouselView.cs
index b0be847f..68c387b6 100644
--- a/Xamarin.Forms.Core/CarouselView.cs
+++ b/Xamarin.Forms.Core/CarouselView.cs
@@ -24,10 +24,8 @@ namespace Xamarin.Forms
 				defaultBindingMode: BindingMode.TwoWay
 			);
 
-		#region Fields
 		object _lastItem;
 		int _lastPosition;
-		#endregion
 
 		public CarouselView()
 		{
@@ -37,14 +35,12 @@ namespace Xamarin.Forms
 			HorizontalOptions = LayoutOptions.FillAndExpand;
 		}
 
-		#region Private Members
 		object GetItem(int position)
 		{
 			var controller = (IItemViewController)this;
 			object item = controller.GetItem(position);
 			return item;
 		}
-		#endregion
 
 		// non-public bc unable to implement on iOS
 		internal event EventHandler<ItemVisibilityEventArgs> ItemAppearing;
@@ -55,9 +51,10 @@ namespace Xamarin.Forms
 			get { return (int)GetValue(PositionProperty); }
 			set { SetValue(PositionProperty, value); }
 		}
-		public int Item
+		public object Item
 		{
-			get { return (int)GetValue(ItemProperty); }
+			get { return GetValue(ItemProperty); }
+			internal set { SetValue(ItemProperty, value); }
 		}
 
 		public event EventHandler<SelectedItemChangedEventArgs> ItemSelected;
@@ -81,16 +78,18 @@ namespace Xamarin.Forms
 		{
 			if (item.Equals(_lastItem))
 				return;
-
-			ItemSelected?.Invoke(this, new SelectedItemChangedEventArgs(item));
 			_lastItem = item;
+
+            Item = item;
+            ItemSelected?.Invoke(this, new SelectedItemChangedEventArgs(item));
 		}
 		void ICarouselViewController.SendSelectedPositionChanged(int position)
 		{
 			if (_lastPosition == position)
 				return;
-
 			_lastPosition = position;
+
+            Item = ((IItemViewController)this).GetItem(position);
 			PositionSelected?.Invoke(this, new SelectedPositionChangedEventArgs(position));
 		}
 	}
diff --git a/Xamarin.Forms.Core/IItemViewController.cs b/Xamarin.Forms.Core/IItemViewController.cs
index 79f711e9..0876f602 100644
--- a/Xamarin.Forms.Core/IItemViewController.cs
+++ b/Xamarin.Forms.Core/IItemViewController.cs
@@ -6,5 +6,6 @@
 		View CreateView(object itemType);
 		object GetItem(int index);
 		object GetItemType(object item);
+        int Count { get; }
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Core/ItemsViewSimple.cs b/Xamarin.Forms.Core/ItemsViewSimple.cs
index 51b9df7a..59858d22 100644
--- a/Xamarin.Forms.Core/ItemsViewSimple.cs
+++ b/Xamarin.Forms.Core/ItemsViewSimple.cs
@@ -30,8 +30,6 @@ namespace Xamarin.Forms
 		{
 		}
 
-		public int Count => _itemSource.Count;
-
 		public IEnumerable ItemsSource
 		{
 			get { return (IEnumerable)GetValue(ItemsSourceProperty); }
@@ -44,6 +42,8 @@ namespace Xamarin.Forms
 			set { SetValue(ItemTemplateProperty, value); }
 		}
 
+		int IItemViewController.Count => _itemSource.Count;
+
 		void IItemViewController.BindView(View view, object item)
 		{
 			view.BindingContext = item;
@@ -192,21 +192,6 @@ namespace Xamarin.Forms
 				return new Enumerator(this);
 			}
 
-			public int IndexOf(object item)
-			{
-				// madness ported from listProxy
-				CollectionSynchronizationContext syncContext = SyncContext;
-				if (syncContext != null)
-				{
-					int value = -1;
-					syncContext.Callback(Enumerable, SyncContext.Context, () => value = _indexable.IndexOf(item), false);
-
-					return value;
-				}
-
-				return _indexable.IndexOf(item);
-			}
-
 			void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
 			{
 				Action onCollectionChanged = () =>
diff --git a/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs
index 0056a1f8..55d9b0df 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs
@@ -521,7 +521,7 @@ namespace Xamarin.Forms.Platform.Android
 					break;
 
 				case NotifyCollectionChangedAction.Remove:
-					if (Element.Count == 0)
+					if (Controller.Count == 0)
 						throw new InvalidOperationException("CarouselView must retain a least one item.");
 
 					Adapter.NotifyItemRangeRemoved(
@@ -1189,8 +1189,9 @@ namespace Xamarin.Forms.Platform.Android
 
 		public override int ItemCount
 		{
-			get {
-				return Element.Count;
+			get
+            {
+				return Controller.Count;
 			}
 		}
 		public override int GetItemViewType(int position)
diff --git a/Xamarin.Forms.Platform.UAP/Resources.xaml b/Xamarin.Forms.Platform.UAP/Resources.xaml
index 23753c13..b66958bf 100644
--- a/Xamarin.Forms.Platform.UAP/Resources.xaml
+++ b/Xamarin.Forms.Platform.UAP/Resources.xaml
@@ -56,6 +56,10 @@
 		</Setter>
 	</Style>
 
+    <DataTemplate x:Key="ItemTemplate">
+        <uwp:ItemControl HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />
+    </DataTemplate>
+
 	<ControlTemplate TargetType="ContentDialog" x:Key="MyContentDialogControlTemplate">
 		<Border x:Name="Container">
 			<Grid x:Name="LayoutRoot">
diff --git a/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs b/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs
index 3e1fd096..e4ff754c 100644
--- a/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs
@@ -45,7 +45,11 @@ namespace Xamarin.Forms.Platform.WinRT
 			{
 				if (_flipView == null)
 				{
-					_flipView = new FlipView { IsSynchronizedWithCurrentItem = false, ItemTemplate = (WDataTemplate)WApp.Current.Resources["ItemTemplate"] };
+					_flipView = new FlipView 
+					{
+						IsSynchronizedWithCurrentItem = false,
+						ItemTemplate = (WDataTemplate)WApp.Current.Resources["ItemTemplate"]
+					};
 				}
 
 				_flipView.ItemsSource = Element.ItemsSource;
@@ -89,7 +93,7 @@ namespace Xamarin.Forms.Platform.WinRT
 					break;
 
 				case NotifyCollectionChangedAction.Remove:
-					if (Element.Count == 0)
+					if (Controller.Count == 0)
 						throw new InvalidOperationException("CarouselView must retain a least one item.");
 
 					if (e.OldStartingIndex < Element.Position)
diff --git a/Xamarin.Forms.Platform.iOS/Renderers/CarouselViewRenderer.cs b/Xamarin.Forms.Platform.iOS/Renderers/CarouselViewRenderer.cs
index 3efb316b..5bc2b8de 100644
--- a/Xamarin.Forms.Platform.iOS/Renderers/CarouselViewRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/Renderers/CarouselViewRenderer.cs
@@ -55,16 +55,9 @@ namespace Xamarin.Forms.Platform.iOS
 
 		int _position;
 		CarouselViewController _controller;
+		RectangleF _lastBounds;
 		#endregion
 
-		new UIScrollView Control
-		{
-			get
-			{
-				Initialize();
-				return base.Control;
-			}
-		}
 		ICarouselViewController Controller
 		{
 			get { return Element; }
@@ -76,6 +69,7 @@ namespace Xamarin.Forms.Platform.iOS
 			if (carouselView != null)
 				return;
 
+			_lastBounds = Bounds;
 			_controller = new CarouselViewController(
 				renderer: this,
 				initialPosition: Element.Position
@@ -141,7 +135,7 @@ namespace Xamarin.Forms.Platform.iOS
 					break;
 
 				case NotifyCollectionChangedAction.Remove:
-					if (Element.Count == 0)
+					if (Controller.Count == 0)
 						throw new InvalidOperationException("CarouselView must retain a least one item.");
 
 					if (e.OldStartingIndex == _position)
@@ -149,7 +143,7 @@ namespace Xamarin.Forms.Platform.iOS
 						_controller.DeleteItems(
 							Enumerable.Range(e.OldStartingIndex, e.OldItems.Count)
 						);
-						if (_position == Element.Count)
+						if (_position == Controller.Count)
 							_position--;
 						OnItemChange(_position);
 					}
@@ -220,6 +214,17 @@ namespace Xamarin.Forms.Platform.iOS
 			}
 		}
 
+		public override void LayoutSubviews()
+		{
+			base.LayoutSubviews();
+
+			if (_lastBounds == Bounds)
+				return;
+
+			base.Control.ReloadData();
+			_lastBounds = Bounds;
+			_controller.ScrollToPosition(_position, false);
+		}
 		public override SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
 		{
 			return Control.GetSizeRequest(widthConstraint, heightConstraint, DefaultMinimumDimension, DefaultMinimumDimension);
@@ -352,7 +357,7 @@ namespace Xamarin.Forms.Platform.iOS
 		}
 		public override nint GetItemsCount(UICollectionView collectionView, nint section)
 		{
-			var result = Element.Count;
+			var result = Controller.Count;
 			return result;
 		}
 		public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms/IItemViewController.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms/IItemViewController.xml
index 03a410f2..31b59da3 100644
--- a/docs/Xamarin.Forms.Core/Xamarin.Forms/IItemViewController.xml
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms/IItemViewController.xml
@@ -32,6 +32,22 @@
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
+    <Member MemberName="Count">
+      <MemberSignature Language="C#" Value="public int Count { get; }" />
+      <MemberSignature Language="ILAsm" Value=".property instance int32 Count" />
+      <MemberType>Property</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Int32</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+        <value>To be added.</value>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="CreateView">
       <MemberSignature Language="C#" Value="public Xamarin.Forms.View CreateView (object itemType);" />
       <MemberSignature Language="ILAsm" Value=".method public hidebysig newslot virtual instance class Xamarin.Forms.View CreateView(object itemType) cil managed" />
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms/ItemsView.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms/ItemsView.xml
index 6f8d1ca5..19c44e77 100644
--- a/docs/Xamarin.Forms.Core/Xamarin.Forms/ItemsView.xml
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms/ItemsView.xml
@@ -18,22 +18,6 @@
     <remarks>To be added.</remarks>
   </Docs>
   <Members>
-    <Member MemberName="Count">
-      <MemberSignature Language="C#" Value="public int Count { get; }" />
-      <MemberSignature Language="ILAsm" Value=".property instance int32 Count" />
-      <MemberType>Property</MemberType>
-      <AssemblyInfo>
-        <AssemblyVersion>2.0.0.0</AssemblyVersion>
-      </AssemblyInfo>
-      <ReturnValue>
-        <ReturnType>System.Int32</ReturnType>
-      </ReturnValue>
-      <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
-      </Docs>
-    </Member>
     <Member MemberName="ItemsSource">
       <MemberSignature Language="C#" Value="public System.Collections.IEnumerable ItemsSource { get; set; }" />
       <MemberSignature Language="ILAsm" Value=".property instance class System.Collections.IEnumerable ItemsSource" />
@@ -142,6 +126,22 @@
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
+    <Member MemberName="Xamarin.Forms.IItemViewController.Count">
+      <MemberSignature Language="C#" Value="int Xamarin.Forms.IItemViewController.Count { get; }" />
+      <MemberSignature Language="ILAsm" Value=".property instance int32 Xamarin.Forms.IItemViewController.Count" />
+      <MemberType>Property</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Int32</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+        <value>To be added.</value>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="Xamarin.Forms.IItemViewController.CreateView">
       <MemberSignature Language="C#" Value="Xamarin.Forms.View IItemViewController.CreateView (object type);" />
       <MemberSignature Language="ILAsm" Value=".method hidebysig newslot virtual instance class Xamarin.Forms.View Xamarin.Forms.IItemViewController.CreateView(object type) cil managed" />