persist row details expanded state per item

Author: w-ahmad

src/TableView.Properties.cs

@@ -6,6 +6,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace WinUI.TableView;
@@ -359,6 +360,8 @@ public bool ShowFilterItemsCount
     /// </summary>
     internal bool IsEditing { get; private set; }
 
+    internal ConditionalWeakTable<object, TValue<bool>> DetailsPaneStates { get; } = [];
+
     /// <summary>
     /// Gets or sets the filter handler for the TableView.
     /// </summary>

src/TableView.cs

@@ -109,6 +109,7 @@ protected override void PrepareContainerForItemOverride(DependencyObject element
             {
                 row.EnsureCellsStyle(default, item);
                 row.ApplyCellsSelectionState();
+                row.RowPresenter?.ApplyDetailsPaneState(item);
 
                 if (CurrentCellSlot.HasValue)
                 {
@@ -667,6 +668,8 @@ private static TableViewBoundColumn GetTableViewColumnFromType(string? propertyN
     /// </summary>
     private void ItemsSourceChanged(DependencyPropertyChangedEventArgs e)
     {
+        DetailsPaneStates.Clear();
+
         using var defer = _collectionView.DeferRefresh();
         _collectionView.Source = null!;
 

src/TableViewRowPresenter.cs

@@ -3,6 +3,7 @@
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Controls.Primitives;
 using Microsoft.UI.Xaml.Data;
+using Microsoft.UI.Xaml.Input;
 using Microsoft.UI.Xaml.Media;
 using Microsoft.UI.Xaml.Shapes;
 using System;
@@ -13,6 +14,26 @@
 
 namespace WinUI.TableView;
 
+internal class TValue<T> where T : struct
+{
+    public TValue(T value)
+    {
+        Value = value;
+    }
+
+    public T Value { get; }
+
+    public static implicit operator T(TValue<T> value)
+    {
+        return value.Value;
+    }
+
+    public static implicit operator TValue<T>(T value)
+    {
+        return new(value);
+    }
+}
+
 /// <summary>
 /// Represents a control that presents visuals for the <see cref="WinUI.TableView.TableViewRow"/>.
 /// </summary>
@@ -68,8 +89,7 @@ protected override void OnApplyTemplate()
 
         if (_detailsToggleButton is not null)
         {
-            _detailsToggleButton.Checked += OnDetailsToggleButtonChecked;
-            _detailsToggleButton.Unchecked += OnDetailsToggleButtonUnChecked;
+            _detailsToggleButton.Tapped += OnDetailsToggleButtonTapped;
         }
 
         if (_detailsPanel is not null)
@@ -190,11 +210,8 @@ internal void SetRowDetailsVisibility()
         }
         else if (mode is TableViewRowDetailsVisibilityMode.VisibleWhenSelected)
         {
-            if (_detailsToggleButton is not null)
-                _detailsToggleButton.IsChecked = TableViewRow?.IsSelected ?? false;
-            else
-                VisualStates.GoToState(this, false, (TableViewRow?.IsSelected ?? false) ? VisualStates.StateDetailsVisible : VisualStates.StateDetailsCollapsed);
-
+            var state = (TableViewRow?.IsSelected ?? false) ? VisualStates.StateDetailsVisible : VisualStates.StateDetailsCollapsed;
+            VisualStates.GoToState(this, false, state);
             VisualStates.GoToState(this, false, VisualStates.StateDetailsButtonCollapsed);
         }
         else if (mode is TableViewRowDetailsVisibilityMode.VisibleWhenExpanded)
@@ -209,19 +226,37 @@ internal void SetRowDetailsVisibility()
     }
 
     /// <summary>
-    /// Handles the Checked event of the details toggle button.
+    /// Handles the Tapped event of the details toggle button.
     /// </summary>
-    private void OnDetailsToggleButtonChecked(object sender, RoutedEventArgs e)
+    private void OnDetailsToggleButtonTapped(object sender, TappedRoutedEventArgs e)
     {
-        VisualStates.GoToState(this, false, VisualStates.StateDetailsVisible);
+        ToggleDetailsPane(TableViewRow?.Content, _detailsToggleButton!.IsChecked ?? false);
     }
 
     /// <summary>
-    /// Handles the Unchecked event of the details toggle button.
+    /// Toggles the visibility of the details pane.
     /// </summary>
-    private void OnDetailsToggleButtonUnChecked(object sender, RoutedEventArgs e)
+    private void ToggleDetailsPane(object? content, bool isVisible)
     {
-        VisualStates.GoToState(this, false, VisualStates.StateDetailsCollapsed);
+        if (TableView is null || content is null) return;
+
+        TableView.DetailsPaneStates.AddOrUpdate(content, isVisible);
+        var state = isVisible ? VisualStates.StateDetailsVisible : VisualStates.StateDetailsCollapsed;
+        VisualStates.GoToState(this, false, state);
+    }
+
+    /// <summary>
+    /// Ensures that the details pane visibility is synchronized for the specified item when row.
+    /// </summary>
+    internal void ApplyDetailsPaneState(object? item)
+    {
+        if (TableView?.RowDetailsVisibilityMode is TableViewRowDetailsVisibilityMode.VisibleWhenExpanded &&
+            _detailsToggleButton is not null && TableView is not null && item is not null)
+        {
+            var isChecked = TableView.DetailsPaneStates.TryGetValue(item, out var value) ? value.Value : false;
+            _detailsToggleButton!.IsChecked = isChecked;
+            ToggleDetailsPane(item, isChecked);
+        }
     }
 
     /// <summary>