Feature: Keep scroll offset when changing item size (#14914)

Author: yair100

src/Files.App/Views/Layouts/ColumnLayoutPage.xaml

@@ -191,6 +191,7 @@
 					IsRightTapEnabled="True"
 					IsTabStop="True"
 					ItemsSource="{x:Bind CollectionViewSource.View, Mode=OneWay}"
+					Loaded="FileList_Loaded"
 					PreviewKeyDown="FileList_PreviewKeyDown"
 					RightTapped="FileList_RightTapped"
 					ScrollViewer.IsScrollInertiaEnabled="True"

src/Files.App/Views/Layouts/ColumnLayoutPage.xaml.cs

@@ -40,7 +40,7 @@ public sealed partial class ColumnLayoutPage : BaseGroupableLayoutPage
 
 		protected override ListViewBase ListViewBase => FileList;
 		protected override SemanticZoom RootZoom => RootGridZoom;
-
+		public ScrollViewer? ContentScroller { get; private set; }
 
 		/// <summary>
 		/// Row height in the Columns View
@@ -66,6 +66,11 @@ public ColumnLayoutPage() : base()
 
 		// Methods
 
+		private void FileList_Loaded(object sender, RoutedEventArgs e)
+		{
+			ContentScroller = FileList.FindDescendant<ScrollViewer>(x => x.Name == "ScrollViewer");
+		}
+
 		private void ColumnViewBase_GotFocus(object sender, RoutedEventArgs e)
 		{
 			if (FileList.SelectedItem == null && openedFolderPresenter != null)
@@ -167,14 +172,18 @@ protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
 
 		private void LayoutSettingsService_PropertyChanged(object? sender, PropertyChangedEventArgs e)
 		{
-			// TODO keep scroll position when changing styles (see details view)
-
 			if (e.PropertyName == nameof(ILayoutSettingsService.ColumnsViewSize))
 			{
+				// Get current scroll position
+				var previousOffset = ContentScroller?.VerticalOffset;
+
 				NotifyPropertyChanged(nameof(RowHeight));
 
 				// Update the container style to match the item size
 				SetItemContainerStyle();
+
+				// Restore correct scroll position
+				ContentScroller?.ChangeView(null, previousOffset, null);
 			}
 		}
 

src/Files.App/Views/Layouts/GridLayoutPage.xaml

@@ -778,6 +778,7 @@
 					IsTabStop="True"
 					ItemContainerTransitions="{x:Null}"
 					ItemsSource="{x:Bind CollectionViewSource.View, Mode=OneWay}"
+					Loaded="FileList_Loaded"
 					PreviewKeyDown="FileList_PreviewKeyDown"
 					ScrollViewer.IsHorizontalScrollChainingEnabled="False"
 					SelectionChanged="FileList_SelectionChanged"

src/Files.App/Views/Layouts/GridLayoutPage.xaml.cs

@@ -28,6 +28,8 @@ public sealed partial class GridLayoutPage : BaseGroupableLayoutPage
 
 		// Properties
 
+		public ScrollViewer? ContentScroller { get; private set; }
+
 		protected override ListViewBase ListViewBase => FileList;
 		protected override SemanticZoom RootZoom => RootGridZoom;
 
@@ -147,7 +149,9 @@ protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
 
 		private void LayoutSettingsService_PropertyChanged(object? sender, PropertyChangedEventArgs e)
 		{
-			// TODO keep scroll position when changing styles (see details view)
+			// Get current scroll position
+			var previousHorizontalOffset = ContentScroller?.HorizontalOffset;
+			var previousVerticalOffset = ContentScroller?.VerticalOffset;
 
 			if (e.PropertyName == nameof(ILayoutSettingsService.ListViewSize))
 			{
@@ -175,6 +179,9 @@ private void LayoutSettingsService_PropertyChanged(object? sender, PropertyChang
 
 				FolderSettings_IconHeightChanged();
 			}
+
+			// Restore correct scroll position
+			ContentScroller?.ChangeView(previousHorizontalOffset, previousVerticalOffset, null);
 		}
 
 		private async void FolderSettings_LayoutModeChangeRequested(object? sender, LayoutModeEventArgs e)
@@ -249,6 +256,11 @@ private void SetItemContainerStyle()
 			}
 		}
 
+		private void FileList_Loaded(object sender, RoutedEventArgs e)
+		{
+			ContentScroller = FileList.FindDescendant<ScrollViewer>(x => x.Name == "ScrollViewer");
+		}
+
 		protected override void FileList_SelectionChanged(object sender, SelectionChangedEventArgs e)
 		{
 			base.FileList_SelectionChanged(sender, e);