Fix: Navigating using left/right arrows in the column layout no longer crashes the app

src/Files.App/Views/LayoutModes/ColumnViewBase.xaml.cs

@@ -399,20 +399,21 @@ private async void FileList_PreviewKeyDown(object sender, KeyRoutedEventArgs e)
 			}
 			else if (e.Key == VirtualKey.Left) // Left arrow: select parent folder (previous column)
 			{
-				if (!IsRenamingItem && !ParentShellPageInstance.ToolbarViewModel.IsEditModeEnabled)
-				{
-					if ((ParentShellPageInstance as ColumnShellPage)?.ColumnParams.Column > 0)
-						FocusManager.TryMoveFocus(FocusNavigationDirection.Previous);
-					e.Handled = true;
-				}
+				if (IsRenamingItem || (ParentShellPageInstance is not null && ParentShellPageInstance.ToolbarViewModel.IsEditModeEnabled) )
+					return;
+
+				var currentBladeIndex = (ParentShellPageInstance is ColumnShellPage associatedColumnShellPage) ? associatedColumnShellPage.ColumnParams.Column : 0;
+				this.FindAscendant<ColumnViewBrowser>()?.MoveFocusToPreviousBlade(currentBladeIndex);
+				e.Handled = true;
 			}
 			else if (e.Key == VirtualKey.Right) // Right arrow: switch focus to next column
 			{
-				if (!IsRenamingItem && !ParentShellPageInstance.ToolbarViewModel.IsEditModeEnabled)
-				{
-					FocusManager.TryMoveFocus(FocusNavigationDirection.Next);
-					e.Handled = true;
-				}
+				if (IsRenamingItem || (ParentShellPageInstance is not null && ParentShellPageInstance.ToolbarViewModel.IsEditModeEnabled)) 
+					return;
+
+				var currentBladeIndex = (ParentShellPageInstance is ColumnShellPage associatedColumnShellPage) ? associatedColumnShellPage.ColumnParams.Column : 0;
+				this.FindAscendant<ColumnViewBrowser>()?.MoveFocusToNextBlade(currentBladeIndex + 1);
+				e.Handled = true;
 			}
 		}
 
@@ -429,7 +430,7 @@ protected override void Page_CharacterReceived(UIElement sender, CharacterReceiv
 
 			if
 			(
-				Microsoft.UI.Input.InputKeyboardSource.GetKeyStateForCurrentThread(VirtualKey.Enter) == CoreVirtualKeyStates.Down ||
+				InputKeyboardSource.GetKeyStateForCurrentThread(VirtualKey.Enter) == CoreVirtualKeyStates.Down ||
 				focusedElement is Button ||
 				focusedElement is TextBox ||
 				focusedElement is PasswordBox ||

src/Files.App/Views/LayoutModes/ColumnViewBrowser.xaml.cs

@@ -205,6 +205,50 @@ public void NavigateUp()
 			}
 		}
 
+		public void MoveFocusToPreviousBlade(int currentBladeIndex)
+		{
+			if (currentBladeIndex <= 0)
+				return;
+
+			DismissOtherBlades(currentBladeIndex);
+
+			var activeBlade = ColumnHost.ActiveBlades[currentBladeIndex - 1];
+			activeBlade.Focus(FocusState.Programmatic);
+
+			var activeBladeColumnViewBase = RetrieveBladeColumnViewBase(activeBlade);
+			if (activeBladeColumnViewBase is null)
+				return;
+
+			//This allows to deselect and reselect the parent folder, hence forcing the refocus.
+			var selectedItem = activeBladeColumnViewBase.FileList.SelectedItem;
+			activeBladeColumnViewBase.FileList.SelectedItem = null;
+			activeBladeColumnViewBase.FileList.SelectedItem = selectedItem;
+		}
+
+		public void MoveFocusToNextBlade(int currentBladeIndex)
+		{
+			if (currentBladeIndex >= ColumnHost.ActiveBlades.Count)
+				return;
+
+			var activeBlade = ColumnHost.ActiveBlades[currentBladeIndex];
+			activeBlade.Focus(FocusState.Programmatic);
+
+			var activeBladeColumnViewBase = RetrieveBladeColumnViewBase(activeBlade);
+			if (activeBladeColumnViewBase is not null)
+				activeBladeColumnViewBase.FileList.SelectedIndex = 0;
+		}
+
+		private ColumnViewBase? RetrieveBladeColumnViewBase(BladeItem blade)
+		{
+			if (blade.Content is not Frame activeBladeFrame)
+				return null;
+
+			if (activeBladeFrame.Content is not ColumnShellPage activeBladePage)
+				return null;
+
+			return activeBladePage.SlimContentPage as ColumnViewBase;
+		}
+
 		public void SetSelectedPathOrNavigate(string navigationPath, Type sourcePageType, NavigationArguments navArgs = null)
 		{
 			var destPath = navArgs is not null ? (navArgs.IsSearchResultPage ? navArgs.SearchPathParam : navArgs.NavPathParam) : navigationPath;