[Win 8.1] Initial ListView selection not shown (#174)

On Windows 8.1, when initially setting a ListView's SelectedItem, the
item in question would not have any visual indication that it was
selected when first showing (a background color for the cell).
Subsequent selections would work as expected.

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla41078.cs

@@ -0,0 +1,36 @@
+using System;
+
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using System.Collections.Generic;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 41078, "[Win 8.1] ListView not visually setting the initial SelectedItem upon creation", PlatformAffected.WinRT)]
+	public class Bugzilla41078 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var list = new List<int> { 1, 2, 3 };
+			var listView = new ListView
+			{
+				ItemsSource = list,
+				SelectedItem = list[1]
+			};
+			Content = new StackLayout
+			{
+				Children =
+				{
+					new Label { Text = "The '2' cell should have a background color indicating it is selected" },
+					listView
+				}
+			};
+		}
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -104,6 +104,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40185.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40333.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla31806.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41078.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34727.cs" />

Xamarin.Forms.Platform.WinRT/ListViewRenderer.cs

@@ -83,6 +83,12 @@ namespace Xamarin.Forms.Platform.WinRT
 				// WinRT throws an exception if you set ItemsSource directly to a CVS, so bind it.
 				List.DataContext = new CollectionViewSource { Source = Element.ItemsSource, IsSourceGrouped = Element.IsGroupingEnabled };
 
+#if !WINDOWS_UWP
+				var selected = Element.SelectedItem;
+				if (selected != null)
+					OnElementItemSelected(null, new SelectedItemChangedEventArgs(selected));
+#endif
+
 				UpdateGrouping();
 				UpdateHeader();
 				UpdateFooter();