UWP CollectionView cleanup (#6928)

* Move files to CollectionView folder for consistency with other platforms
Move SelectableItemsViewRenderer to Setup/Teardown pattern
Fix event handler naming
Use Is method for property changed check

* Rebase cleanup

.nuspec/Xamarin.Forms.nuspec

@@ -221,7 +221,7 @@
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\TabbedPageStyle.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\FormsEmbeddedPageWrapper.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\StepperControl.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
-    <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\Items\ItemsViewStyles.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP\Items" />
+    <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\CollectionView\ItemsViewStyles.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP\Items" />
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\FormsCheckBoxStyle.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
 
     <!--Mac-->

Xamarin.Forms.Platform.UAP/CollectionView/ItemsViewRenderer.cs

@@ -183,9 +183,9 @@ namespace Xamarin.Forms.Platform.UWP
 			return horizontalListView;
 		}
 
-		void LayoutOnPropertyChanged(object sender, PropertyChangedEventArgs e)
+		void LayoutPropertyChanged(object sender, PropertyChangedEventArgs property)
 		{
-			if (e.PropertyName == GridItemsLayout.SpanProperty.PropertyName)
+			if (property.Is(GridItemsLayout.SpanProperty))
 			{
 				if (ListViewBase is FormsGridView formsGridView)
 				{
@@ -194,7 +194,7 @@ namespace Xamarin.Forms.Platform.UWP
 			}
 		}
 
-		void SetUpNewElement(ItemsView newElement)
+		protected virtual void SetUpNewElement(ItemsView newElement)
 		{
 			if (newElement == null)
 			{
@@ -206,7 +206,7 @@ namespace Xamarin.Forms.Platform.UWP
 				ListViewBase = SelectLayout(newElement.ItemsLayout);
 
 				_layout = newElement.ItemsLayout;
-				_layout.PropertyChanged += LayoutOnPropertyChanged;
+				_layout.PropertyChanged += LayoutPropertyChanged;
 
 				SetNativeControl(ListViewBase);
 			}
@@ -220,7 +220,7 @@ namespace Xamarin.Forms.Platform.UWP
 			newElement.ScrollToRequested += ScrollToRequested;
 		}
 
-		void TearDownOldElement(ItemsView oldElement)
+		protected virtual void TearDownOldElement(ItemsView oldElement)
 		{
 			if (oldElement == null)
 			{
@@ -230,7 +230,7 @@ namespace Xamarin.Forms.Platform.UWP
 			if (_layout != null)
 			{
 				// Stop tracking the old layout
-				_layout.PropertyChanged -= LayoutOnPropertyChanged;
+				_layout.PropertyChanged -= LayoutPropertyChanged;
 				_layout = null;
 			}
 

Xamarin.Forms.Platform.UAP/CollectionView/SelectableItemsViewRenderer.cs

@@ -10,7 +10,7 @@ namespace Xamarin.Forms.Platform.UWP
 	{
 		SelectableItemsView _selectableItemsView;
 
-		protected override void OnElementChanged(ElementChangedEventArgs<CollectionView> args)
+		protected override void TearDownOldElement(ItemsView oldElement)
 		{
 			var oldListViewBase = ListViewBase;
 			if (oldListViewBase != null)
@@ -19,13 +19,19 @@ namespace Xamarin.Forms.Platform.UWP
 				oldListViewBase.SelectionChanged -= OnNativeSelectionChanged;
 			}
 
-			if (args.OldElement != null)
+			if (_selectableItemsView != null)
 			{
-				args.OldElement.SelectionChanged -= OnSelectionChanged;
+				_selectableItemsView.SelectionChanged -= OnSelectionChanged;
 			}
 
-			base.OnElementChanged(args);
-			_selectableItemsView = args.NewElement;
+			base.TearDownOldElement(oldElement);
+		}
+
+		protected override void SetUpNewElement(ItemsView newElement)
+		{
+			base.SetUpNewElement(newElement);
+
+			_selectableItemsView = newElement as SelectableItemsView;
 
 			if (_selectableItemsView != null)
 			{
@@ -47,6 +53,7 @@ namespace Xamarin.Forms.Platform.UWP
 
 				newListViewBase.SelectionChanged += OnNativeSelectionChanged;
 			}
+
 			UpdateNativeSelection();
 		}
 

Xamarin.Forms.Platform.UAP/Resources.xaml

@@ -14,7 +14,7 @@
 		<ResourceDictionary Source="MasterDetailControlStyle.xaml" />
 		<ResourceDictionary Source="TabbedPageStyle.xaml" />
 		<ResourceDictionary Source="SliderStyle.xaml" />
-		<ResourceDictionary Source="Items/ItemsViewStyles.xaml" />
+		<ResourceDictionary Source="CollectionView/ItemsViewStyles.xaml" />
 	</ResourceDictionary.MergedDictionaries>
 	
 	<uwp:CaseConverter x:Key="LowerConverter" ConvertToUpper="False" />

Xamarin.Forms.Platform.UAP/Xamarin.Forms.Platform.UAP.csproj

@@ -53,7 +53,7 @@
     <Compile Include="AlertDialog.cs" />
     <Compile Include="IDontGetFocus.cs" />
     <Compile Include="FontImageSourceHandler.cs" />
-    <Compile Include="Items\ItemContentControl.cs" />
+    <Compile Include="CollectionView\ItemContentControl.cs" />
     <Compile Include="FormsPivot.cs" />
     <Compile Include="AlignmentExtensions.cs" />
     <Compile Include="BrushHelpers.cs" />
@@ -66,13 +66,13 @@
     <Compile Include="ImageElementManager.cs" />
     <Compile Include="InterceptVisualStateManager.cs" />
     <Compile Include="HorizontalTextAlignmentConverter.cs" />
-    <Compile Include="Items\ObservableItemTemplateCollection.cs" />
-    <Compile Include="Items\TemplatedItemSourceFactory.cs" />
+    <Compile Include="CollectionView\ObservableItemTemplateCollection.cs" />
+    <Compile Include="CollectionView\TemplatedItemSourceFactory.cs" />
     <Compile Include="ITitleIconProvider.cs" />
     <Compile Include="ITitleViewProvider.cs" />
-    <Compile Include="Items\FormsGridView.cs" />
-    <Compile Include="Items\ItemTemplateEnumerator.cs" />
-    <Compile Include="Items\ItemTemplateContext.cs" />
+    <Compile Include="CollectionView\FormsGridView.cs" />
+    <Compile Include="CollectionView\ItemTemplateEnumerator.cs" />
+    <Compile Include="CollectionView\ItemTemplateContext.cs" />
     <Compile Include="ITitleProvider.cs" />
     <Compile Include="ITitleViewRendererController.cs" />
     <Compile Include="IToolbarProvider.cs" />
@@ -219,7 +219,7 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
-    <Page Include="Items\ItemsViewStyles.xaml">
+    <Page Include="CollectionView\ItemsViewStyles.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>