fix(listview): account for panel orientation

src/Uno.UI/UI/Xaml/Controls/ItemsStackPanel/ItemsStackPanel.cs

@@ -20,6 +20,8 @@ public partial class ItemsStackPanel : Panel, IVirtualizingPanel
 #endif
 		public int LastVisibleIndex => _layout?.LastVisibleIndex ?? -1;
 
+		internal override Orientation? InternalOrientation => Orientation;
+
 #if __ANDROID__
 		public int FirstCacheIndex => _layout.XamlParent.NativePanel.ViewCache.FirstCacheIndex;
 		public int LastCacheIndex => _layout.XamlParent.NativePanel.ViewCache.LastCacheIndex;

src/Uno.UI/UI/Xaml/Controls/ItemsWrapGrid/ItemsWrapGrid.cs

@@ -14,6 +14,8 @@ public partial class ItemsWrapGrid : Panel, IVirtualizingPanel
 
 		public int LastVisibleIndex => _layout?.LastVisibleIndex ?? -1;
 
+		internal override Orientation? InternalOrientation => Orientation;
+
 #if __ANDROID__
 		public int FirstCacheIndex => _layout.XamlParent.NativePanel.ViewCache.FirstCacheIndex;
 		public int LastCacheIndex => _layout.XamlParent.NativePanel.ViewCache.LastCacheIndex;

src/Uno.UI/UI/Xaml/Controls/ListViewBase/ListViewBase.cs

@@ -105,13 +105,21 @@ internal bool TryHandleKeyDown(KeyRoutedEventArgs args)
 					OnItemClicked(focusedContainer, args.KeyboardModifiers);
 				}
 			}
-			else if (args.Key == VirtualKey.Down)
-			{
-				return TryMoveKeyboardFocusAndSelection(+1, args.KeyboardModifiers);
-			}
-			else if (args.Key == VirtualKey.Up)
+			else
 			{
-				return TryMoveKeyboardFocusAndSelection(-1, args.KeyboardModifiers);
+				var orientation = ItemsPanelRoot.InternalOrientation ?? Orientation.Vertical;
+
+				switch (args.Key)
+				{
+					case VirtualKey.Down when orientation == Orientation.Vertical:
+						return TryMoveKeyboardFocusAndSelection(+1, args.KeyboardModifiers);
+					case VirtualKey.Up when orientation == Orientation.Vertical:
+						return TryMoveKeyboardFocusAndSelection(-1, args.KeyboardModifiers);
+					case VirtualKey.Right when orientation == Orientation.Horizontal:
+						return TryMoveKeyboardFocusAndSelection(+1, args.KeyboardModifiers);
+					case VirtualKey.Left when orientation == Orientation.Horizontal:
+						return TryMoveKeyboardFocusAndSelection(-1, args.KeyboardModifiers);
+				}
 			}
 			return false;
 		}
@@ -124,6 +132,11 @@ private bool TryMoveKeyboardFocusAndSelection(int offset, VirtualKeyModifiers mo
 			var newContainer = ContainerFromIndex(newIndex) as SelectorItem;
 			var newItem = ItemFromIndex(newIndex);
 
+			if (newIndex < 0 || newIndex >= Items.Count)
+			{
+				return false;
+			}
+
 			FocusedIndexContainerItem = (newIndex, newContainer, newItem);
 
 			switch (SelectionMode)

src/Uno.UI/UI/Xaml/Controls/Panel/Panel.cs

@@ -106,6 +106,13 @@ private static void OnChildrenTransitionsChanged(object dependencyObject, Depend
 
 		#endregion
 
+		/// <summary>
+		/// Panels don't have an Orientation in UWP, but many derived types do.
+		/// This should be overriden by the derived types to refer to match their
+		/// own Orientation.
+		/// </summary>
+		internal virtual Orientation? InternalOrientation { get; }
+
 		internal Thickness PaddingInternal { get; set; }
 
 		internal Thickness BorderThicknessInternal { get; set; }

src/Uno.UI/UI/Xaml/Controls/StackPanel/StackPanel.cs

@@ -138,6 +138,8 @@ private void OnCornerRadiusPropertyChanged(CornerRadius oldValue, CornerRadius n
 
 		#region Orientation DependencyProperty
 
+		internal override Orientation? InternalOrientation => Orientation;
+
 		public Orientation Orientation
 		{
 			get { return (Orientation)GetValue(OrientationProperty); }

src/Uno.UI/UI/Xaml/Controls/VirtualizingPanel.cs

@@ -13,5 +13,7 @@ public VirtualizingPanel()
 		public VirtualizingPanelLayout GetLayouter() => GetLayouterCore();
 
 		private protected virtual VirtualizingPanelLayout GetLayouterCore() => throw new NotSupportedException($"This method must be overridden by implementing classes.");
+
+		internal override Orientation? InternalOrientation => GetLayouter().Orientation;
 	}
 }