Merge pull request w-ahmad#369 from w-ahmad/fix/memory-issues

fix: Improvements and fixes for memory management

Author: w-ahmad

samples/WinUI.TableView.SampleApp/MainPage.xaml

@@ -187,7 +187,8 @@
             <NavigationView.Content>
                 <Grid>
                     <Frame x:Name="rootFrame"
-                           IsNavigationStackEnabled="False"
+                           CacheSize="0"
+                           IsNavigationStackEnabled="True"
                            Navigated="OnRootFrameNavigated"
                            IsEnabled="{Binding Visibility, ElementName=loadingIndicator, Converter={StaticResource VisibilityToBool}}" />
                     <StackPanel x:Name="loadingIndicator"

samples/WinUI.TableView.SampleApp/MainPage.xaml.cs

@@ -17,7 +17,6 @@ public sealed partial class MainPage : Page
     public MainPage()
     {
         InitializeComponent();
-
         App.Current.MainWindow.Activated += OnMainWindowActivated;
         App.Current.MainWindow.SetTitleBar(AppTitleBar);
 
@@ -139,12 +138,17 @@ private async void OnRootFrameNavigated(object sender, NavigationEventArgs e)
             navigationView.SelectedItem = navItem;
         }
 
-        if (e.Content is Page { DataContext: null } page)
+        if (e.Content is Page page)
         {
-            await Task.Delay(10);
-            page.DataContext = new ExampleViewModel();
+            page.NavigationCacheMode = NavigationCacheMode.Disabled;
+
+            if (page.DataContext is null)
+            {
+                await Task.Delay(10);
+                page.DataContext = new ExampleViewModel();
+            }
         }
 
         _canNavigate = true;
     }
-}
+}

samples/WinUI.TableView.SampleApp/Pages/ConditionalStylingPage.xaml

@@ -7,7 +7,8 @@
       xmlns:tv="using:WinUI.TableView"
       xmlns:controls="using:WinUI.TableView.SampleApp.Controls"
       mc:Ignorable="d"
-      Loaded="OnPageLoaded">
+      Loaded="OnPageLoaded"
+      Unloaded="OnPageUnloaded">
 
     <Page.DataContext>
         <local:SalesViewModel />

samples/WinUI.TableView.SampleApp/Pages/ConditionalStylingPage.xaml.cs

@@ -26,6 +26,12 @@ private async void OnPageLoaded(object sender, RoutedEventArgs e)
         liveUpdates.IsOn = true;
     }
 
+    private void OnPageUnloaded(object sender, RoutedEventArgs e)
+    {
+        StopLiveUpdates();
+        ViewModel.SalesData = null;
+    }
+
     private void OnLiveUpdatesToggled(object sender, RoutedEventArgs e)
     {
         if (liveUpdates.IsOn)
@@ -34,32 +40,52 @@ private void OnLiveUpdatesToggled(object sender, RoutedEventArgs e)
         }
         else
         {
-            _liveUpdatesCST?.Cancel();
-            _liveUpdatesCST = null;
+            StopLiveUpdates();
         }
     }
 
     private async Task StartLiveUpdatesAsync()
     {
+        StopLiveUpdates();
         _liveUpdatesCST = new CancellationTokenSource();
+        var token = _liveUpdatesCST.Token;
 
-        while (ViewModel.SalesData is not null && !_liveUpdatesCST.IsCancellationRequested)
+        try
+        {
+            while (ViewModel.SalesData is not null && !token.IsCancellationRequested)
+            {
+                await Task.Delay((int)updateInterval.Value, token);
+
+                var region = DataFaker.Region();
+                var target = DataFaker.Integer(5_000, 30_000);
+                var sales = DataFaker.Integer((int)(target * 0.5), (int)(target * 1.2));
+                var growth = DataFaker.Integer(-10, 10);
+                var status = sales >= target ? (growth >= 0 ? "Ahead" : "On Track") : (growth < 0 ? "Behind" : "On Track");
+                var item = ViewModel.SalesData[Random.Shared.Next(ViewModel.SalesData.Count)];
+
+                item.Region = region;
+                item.Target = target;
+                item.Sales = sales;
+                item.Growth = growth;
+                item.Status = status;
+            }
+        }
+        catch (OperationCanceledException)
         {
-            await Task.Delay((int)updateInterval.Value, _liveUpdatesCST.Token);
-
-            var region = DataFaker.Region();
-            var target = DataFaker.Integer(5_000, 30_000);
-            var sales = DataFaker.Integer((int)(target * 0.5), (int)(target * 1.2));
-            var growth = DataFaker.Integer(-10, 10);
-            var status = sales >= target ? (growth >= 0 ? "Ahead" : "On Track") : (growth < 0 ? "Behind" : "On Track");
-            var item = ViewModel.SalesData[Random.Shared.Next(ViewModel.SalesData.Count)];
-
-            item.Region = region;
-            item.Target = target;
-            item.Sales = sales;
-            item.Growth = growth;
-            item.Status = status;
         }
+        finally
+        {
+            if (_liveUpdatesCST?.Token == token)
+            {
+                _liveUpdatesCST.Dispose();
+                _liveUpdatesCST = null;
+            }
+        }
+    }
+
+    private void StopLiveUpdates()
+    {
+        _liveUpdatesCST?.Cancel();
     }
 
     private Predicate<TableViewConditionalCellStyleContext> SalesMetTargetPredicate =>

samples/WinUI.TableView.SampleApp/Pages/ExternalFilteringPage.xaml.cs

@@ -11,6 +11,7 @@ public ExternalFilteringPage()
         InitializeComponent();
 
         tableView.FilterDescriptions.Add(new FilterDescription(string.Empty, Filter));
+        Unloaded += OnPageUnloaded;
     }
 
     private bool Filter(object? item)
@@ -46,12 +47,19 @@ private async Task RefreshFilter(CancellationToken token)
         {
             await Task.Delay(200, token);
         }
-        catch
+        catch (OperationCanceledException)
         {
             return;
         }
 
         _token = null;
         tableView.RefreshFilter();
     }
+
+    private void OnPageUnloaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        _token?.Cancel();
+        _token?.Dispose();
+        _token = null;
+    }
 }

samples/WinUI.TableView.SampleApp/Pages/LargeDataPage.xaml

@@ -10,7 +10,8 @@
       xmlns:ui="using:CommunityToolkit.WinUI"
       xmlns:converters="using:WinUI.TableView.SampleApp.Converters"
       mc:Ignorable="d"
-      Loaded="OnPageLoaded">
+      Loaded="OnPageLoaded"
+      Unloaded="OnPageUnloaded">
 
     <Page.DataContext>
         <local:TransactionsViewModel />

samples/WinUI.TableView.SampleApp/Pages/LargeDataPage.xaml.cs

@@ -23,8 +23,18 @@ private void OnSetItemsSourceCliced(object sender, RoutedEventArgs e)
     {
         if (DataContext is TransactionsViewModel viewModel)
         {
-            viewModel.TransacationsData = [.. TransactionsViewModel.TransacationsList];
+            viewModel.TransacationsData = TransactionsViewModel.TransacationsList;
             ((Button)sender).IsEnabled = false;
         }
     }
+
+    private void OnPageUnloaded(object sender, RoutedEventArgs e)
+    {
+        if (DataContext is TransactionsViewModel viewModel)
+        {
+            viewModel.TransacationsData = null;
+        }
+
+        TransactionsViewModel.ReleaseItems();
+    }
 }

samples/WinUI.TableView.SampleApp/TransactionsViewModel.cs

@@ -10,12 +10,11 @@ await Task.Run(() =>
         {
             var startId = 7_475_327;
             var startDate = new DateTime(2010, 1, 1);
-
-            TransacationsList.Clear();
+            var items = new List<TransactionModel>(1_000_000);
 
             for (var i = 0; i < 1_000_000; i++)
             {
-                TransacationsList.Add(new TransactionModel
+                items.Add(new TransactionModel
                 {
                     Id = startId++,
                     Date = startDate.AddMinutes(i),
@@ -30,11 +29,18 @@ await Task.Run(() =>
                     Mcc = DataFaker.Integer(1700, 9500)
                 });
             }
+
+            TransacationsList = items;
         });
     }
 
+    public static void ReleaseItems()
+    {
+        TransacationsList = [];
+    }
+
     [ObservableProperty]
     public partial IList<TransactionModel>? TransacationsData { get; set; }
 
-    public static IList<TransactionModel> TransacationsList { get; set; } = [];
-}
+    public static IList<TransactionModel> TransacationsList { get; private set; } = [];
+}

src/TableView.cs

@@ -36,6 +36,7 @@ public partial class TableView : ListView
     private RowDefinition? _headerRowDefinition;
     private bool _shouldThrowSelectionModeChangedException;
     private bool _ensureColumns = true;
+    private bool _isItemsSourceSuspended;
     private readonly List<TableViewRow> _rows = [];
     private readonly CollectionView _collectionView = [];
 
@@ -108,6 +109,12 @@ protected override void PrepareContainerForItemOverride(DependencyObject element
         {
             if (element is TableViewRow row)
             {
+                if (!_rows.Contains(row))
+                {
+                    _rows.Add(row);
+                }
+
+                row.TableView = this;
                 row.EnsureCellsStyle(default, item);
                 row.ApplyCellsSelectionState();
                 row.RowPresenter?.ApplyDetailsPaneState(item);
@@ -120,6 +127,18 @@ protected override void PrepareContainerForItemOverride(DependencyObject element
         });
     }
 
+    /// <inheritdoc/>
+    protected override void ClearContainerForItemOverride(DependencyObject element, object item)
+    {
+        if (element is TableViewRow row)
+        {
+            _rows.Remove(row);
+            row.TableView = null;
+        }
+
+        base.ClearContainerForItemOverride(element, item);
+    }
+
     /// <inheritdoc/>
     protected override DependencyObject GetContainerForItemOverride()
     {
@@ -363,6 +382,7 @@ private void OnScrollViewerLoaded(object sender, RoutedEventArgs e)
     /// </summary>
     private void OnLoaded(object sender, RoutedEventArgs e)
     {
+        ResumeItemsSource();
         EnsureAutoColumns();
     }
 
@@ -375,6 +395,43 @@ private void OnUnloaded(object sender, RoutedEventArgs e)
         {
             currentCell.EndEditing(TableViewEditAction.Commit);
         }
+
+        SuspendItemsSource();
+    }
+
+    /// <summary>
+    /// Suspends subscriptions to the current items source while the control is unloaded.
+    /// </summary>
+    private void SuspendItemsSource()
+    {
+        if (_isItemsSourceSuspended)
+        {
+            return;
+        }
+
+        _collectionView.ItemPropertyChanged -= OnItemPropertyChanged;
+        _collectionView.Source = Enumerable.Empty<object>();
+        _isItemsSourceSuspended = true;
+    }
+
+    /// <summary>
+    /// Restores subscriptions to the current items source when the control is loaded.
+    /// </summary>
+    private void ResumeItemsSource()
+    {
+        if (!_isItemsSourceSuspended)
+        {
+            return;
+        }
+
+        _collectionView.ItemPropertyChanged += OnItemPropertyChanged;
+
+        if (ItemsSource is IEnumerable source)
+        {
+            _collectionView.Source = source;
+        }
+
+        _isItemsSourceSuspended = false;
     }
 
     /// <summary>
@@ -749,7 +806,10 @@ private void ItemsSourceChanged(DependencyPropertyChangedEventArgs e)
         {
             EnsureAutoColumns();
 
-            _collectionView.Source = source;
+            if (!_isItemsSourceSuspended)
+            {
+                _collectionView.Source = source;
+            }
         }
     }