Keep metadata-row source strongly typed so default sort works

Each metadata tree node was projecting its rows into List<object> via Cast<object>
before assigning to MetadataTablePageModel.Items. That collapsed the source's
element type at the runtime interface chain — DataGridCollectionView.GetItemType
walks IEnumerable<T> and only saw IEnumerable<object>, which made
DataGridSortDescription.Initialize resolve a null propertyType, which made
ReflectionHelper.GetNestedPropertyValue's "propertyInfo.PropertyType != propertyType"
check return null for every row. Result: header click flipped the sort indicator
but the row order never changed.

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy/Metadata/BlobHeapTreeNode.cs

@@ -49,7 +49,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "Blob Heap",
-				Items = EnsureEntries().Cast<object>().ToList(),
+				Items = EnsureEntries(),
 			};
 			MetadataColumnBuilder.Populate<BlobHeapEntry>(page);
 			return page;

ILSpy/Metadata/CoffHeaderTreeNode.cs

@@ -49,7 +49,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "COFF Header",
-				Items = BuildEntries().Cast<object>().ToList(),
+				Items = BuildEntries(),
 			};
 			MetadataColumnBuilder.Populate<Entry>(page);
 			return page;

ILSpy/Metadata/DataDirectoriesTreeNode.cs

@@ -50,7 +50,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "Data Directories",
-				Items = BuildEntries().Cast<object>().ToList(),
+				Items = BuildEntries(),
 			};
 			MetadataColumnBuilder.Populate<DataDirectoryEntry>(page);
 			return page;

ILSpy/Metadata/DebugDirectoryTreeNode.cs

@@ -55,7 +55,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "Debug Directory",
-				Items = BuildEntries().Cast<object>().ToList(),
+				Items = BuildEntries(),
 			};
 			MetadataColumnBuilder.Populate<DebugDirectoryEntryView>(page);
 			return page;

ILSpy/Metadata/DosHeaderTreeNode.cs

@@ -48,7 +48,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "DOS Header",
-				Items = BuildEntries().Cast<object>().ToList(),
+				Items = BuildEntries(),
 			};
 			MetadataColumnBuilder.Populate<Entry>(page);
 			return page;

ILSpy/Metadata/GuidHeapTreeNode.cs

@@ -48,7 +48,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "Guid Heap",
-				Items = EnsureEntries().Cast<object>().ToList(),
+				Items = EnsureEntries(),
 			};
 			MetadataColumnBuilder.Populate<GuidHeapEntry>(page);
 			return page;

ILSpy/Metadata/MetadataTableTreeNode.cs

@@ -58,6 +58,7 @@ namespace ILSpy.Metadata
 	/// them clickable hyperlinks via <see cref="MetadataColumnBuilder"/>.
 	/// </summary>
 	public abstract class MetadataTableTreeNode<TEntry> : MetadataTableTreeNode
+		where TEntry : class
 	{
 		IReadOnlyList<TEntry>? cached;
 
@@ -73,9 +74,16 @@ namespace ILSpy.Metadata
 
 		public override TabPageModel CreateTab()
 		{
+			// IReadOnlyList<T> is covariant on T, so a strongly-typed list passes through to
+			// MetadataTablePageModel.Items (declared as IReadOnlyList<object>) without a
+			// reflective copy. The runtime type stays IReadOnlyList<TEntry>, which lets
+			// DataGridCollectionView.GetItemType find the IEnumerable<TEntry> interface and
+			// resolve property-path sorts correctly — see DataGridSortDescription.Initialize
+			// + ReflectionHelper.GetNestedPropertyValue, which return null for every row when
+			// the source's element type is object.
 			var page = new MetadataTablePageModel {
 				Title = $"{Kind} ({RowCount})",
-				Items = (cached ??= LoadTable()).Cast<object>().ToList(),
+				Items = cached ??= LoadTable(),
 			};
 			MetadataColumnBuilder.Populate<TEntry>(page);
 			return page;

ILSpy/Metadata/OptionalHeaderTreeNode.cs

@@ -50,7 +50,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "Optional Header",
-				Items = BuildEntries().Cast<object>().ToList(),
+				Items = BuildEntries(),
 			};
 			MetadataColumnBuilder.Populate<Entry>(page);
 			return page;

ILSpy/Metadata/StringHeapTreeNode.cs

@@ -49,7 +49,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "String Heap",
-				Items = EnsureEntries().Cast<object>().ToList(),
+				Items = EnsureEntries(),
 			};
 			MetadataColumnBuilder.Populate<StringHeapEntry>(page);
 			return page;

ILSpy/Metadata/UserStringHeapTreeNode.cs

@@ -48,7 +48,7 @@ namespace ILSpy.Metadata
 		{
 			var page = new MetadataTablePageModel {
 				Title = "UserString Heap",
-				Items = EnsureEntries().Cast<object>().ToList(),
+				Items = EnsureEntries(),
 			};
 			MetadataColumnBuilder.Populate<UserStringHeapEntry>(page);
 			return page;

ILSpy/Views/MetadataTablePage.axaml.cs

@@ -69,13 +69,6 @@ namespace ILSpy.Views
 				grid.AddHandler(PointerPressedEvent, OnGridPointerPressed,
 					global::Avalonia.Interactivity.RoutingStrategies.Bubble,
 					handledEventsToo: true);
-				// Manually drive the DataGridCollectionView's SortDescriptions when the user
-				// clicks a column header. ProDataGrid's auto-sort path doesn't reach our
-				// view (Items is IReadOnlyList<object> wrapped in a DataGridCollectionView,
-				// and the default sorting adapter's reflection chain doesn't pick up the
-				// SortMemberPath against an object collection). Toggle ascending → descending
-				// → unsorted on repeated clicks.
-				grid.Sorting += OnGridSorting;
 			}
 		}
 
@@ -334,40 +327,6 @@ namespace ILSpy.Views
 
 		void OnAnyColumnFilterChanged() => itemsView?.Refresh();
 
-		void OnGridSorting(object? sender, DataGridColumnEventArgs e)
-		{
-			// Manually drive sort: cycle through ascending → descending → unsorted on repeated
-			// clicks for the same column. Mark the event handled so ProDataGrid's auto-sort
-			// path doesn't run after us — without this it would try to add another
-			// SortDescription against the same path and produce a stuck "double-sorted" state.
-			if (itemsView is null)
-				return;
-			string? path = (e.Column.SortMemberPath ?? e.Column.Tag as string);
-			if (string.IsNullOrEmpty(path))
-				return;
-
-			var existing = itemsView.SortDescriptions
-				.FirstOrDefault(d => d.PropertyPath == path);
-
-			itemsView.SortDescriptions.Clear();
-			foreach (var col in (sender as DataGrid)?.Columns ?? System.Linq.Enumerable.Empty<DataGridColumn>())
-				col.SortDirection = null;
-
-			if (existing is null)
-			{
-				itemsView.SortDescriptions.Add(DataGridSortDescription.FromPath(path, ListSortDirection.Ascending));
-				e.Column.SortDirection = ListSortDirection.Ascending;
-			}
-			else if (existing.Direction == ListSortDirection.Ascending)
-			{
-				itemsView.SortDescriptions.Add(DataGridSortDescription.FromPath(path, ListSortDirection.Descending));
-				e.Column.SortDirection = ListSortDirection.Descending;
-			}
-			// Third click clears: SortDescriptions stays empty, SortDirection on column is null.
-
-			e.Handled = true;
-		}
-
 		void ApplySchema()
 		{
 			var grid = this.FindControl<DataGrid>("Grid");