Forward column-filter changes via a single page event

The page now subscribes to its own ColumnFilters' PropertyChanged via
CollectionChanged and re-raises ColumnFilterChanged. The view listens
to that single event instead of chasing per-filter listeners on every
schema swap, which was leaving the auto-refresh path silent on the
running app even though the predicate itself was correct.

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

ILSpy.Tests/Metadata/MetadataFilterTests.cs

@@ -89,6 +89,41 @@ public class MetadataFilterTests
 		}).Should().BeFalse();
 	}
 
+	[Test]
+	public void Setting_ColumnFilter_Text_Raises_ColumnFilterChanged_On_The_Page()
+	{
+		// The view subscribes to the page's ColumnFilterChanged event to drive its
+		// DataGridCollectionView.Refresh — without this forwarding the filter row would be
+		// invisible to the grid and typing would have no effect on visible rows.
+		var page = new MetadataTablePageModel();
+		var filter = new ColumnFilter("Name");
+		page.ColumnFilters.Add(filter);
+		var fired = 0;
+		page.ColumnFilterChanged += () => fired++;
+
+		filter.Text = "System";
+
+		fired.Should().Be(1);
+	}
+
+	[Test]
+	public void Removing_A_ColumnFilter_Stops_Forwarding_Its_Text_Changes()
+	{
+		// When Populate clears the collection on a schema swap, the previously-attached
+		// filters must stop driving refreshes — otherwise stale headers from a former tab
+		// would keep firing into the new view's CollectionView.
+		var page = new MetadataTablePageModel();
+		var filter = new ColumnFilter("Name");
+		page.ColumnFilters.Add(filter);
+		page.ColumnFilters.Remove(filter);
+		var fired = 0;
+		page.ColumnFilterChanged += () => fired++;
+
+		filter.Text = "System";
+
+		fired.Should().Be(0);
+	}
+
 	[Test]
 	public void MatchesFilters_Returns_False_When_The_Filtered_Column_Does_Not_Exist_On_The_Row()
 	{

ILSpy/ViewModels/MetadataTablePageModel.cs

@@ -20,6 +20,8 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
 using System.Reflection;
 
 using Avalonia.Controls;
@@ -59,13 +61,34 @@ namespace ILSpy.ViewModels
 		public ObservableCollection<ColumnFilter> ColumnFilters { get; } = new();
 
 		/// <summary>
-		/// Raised whenever any column's filter text changes. The view subscribes to this so
-		/// it can refresh the underlying <c>DataGridCollectionView</c> without each column
-		/// having to know how to find the live view instance.
+		/// Raised whenever any column's filter text changes. The view subscribes here to
+		/// refresh its <c>DataGridCollectionView</c>; tests use it as the canonical filter
+		/// signal too. The page wires this internally via <c>ColumnFilters.CollectionChanged</c>
+		/// + each filter's <see cref="INotifyPropertyChanged"/> so callers don't have to chase
+		/// individual filter instances.
 		/// </summary>
 		public event Action? ColumnFilterChanged;
 
-		internal void RaiseColumnFilterChanged() => ColumnFilterChanged?.Invoke();
+		public MetadataTablePageModel()
+		{
+			ColumnFilters.CollectionChanged += OnColumnFiltersCollectionChanged;
+		}
+
+		void OnColumnFiltersCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
+		{
+			if (e.OldItems is not null)
+				foreach (ColumnFilter f in e.OldItems)
+					f.PropertyChanged -= OnColumnFilterTextChanged;
+			if (e.NewItems is not null)
+				foreach (ColumnFilter f in e.NewItems)
+					f.PropertyChanged += OnColumnFilterTextChanged;
+		}
+
+		void OnColumnFilterTextChanged(object? sender, PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName == nameof(ColumnFilter.Text))
+				ColumnFilterChanged?.Invoke();
+		}
 
 		/// <summary>
 		/// Raised when the user clicks a hyperlink-styled token cell. The host (the dock

ILSpy/Views/MetadataTablePage.axaml.cs

@@ -130,13 +130,13 @@ namespace ILSpy.Views
 			if (boundModel != null)
 			{
 				boundModel.PropertyChanged -= OnModelPropertyChanged;
-				DetachColumnFilterListeners(boundModel);
+				boundModel.ColumnFilterChanged -= OnAnyColumnFilterChanged;
 			}
 			boundModel = DataContext as MetadataTablePageModel;
 			if (boundModel != null)
 			{
 				boundModel.PropertyChanged += OnModelPropertyChanged;
-				AttachColumnFilterListeners(boundModel);
+				boundModel.ColumnFilterChanged += OnAnyColumnFilterChanged;
 			}
 			ApplySchema();
 			ApplyScrollTarget();
@@ -146,37 +146,12 @@ namespace ILSpy.Views
 		{
 			if (e.PropertyName is nameof(MetadataTablePageModel.Columns)
 				or nameof(MetadataTablePageModel.Items))
-			{
-				if (sender is MetadataTablePageModel m)
-				{
-					DetachColumnFilterListeners(m);
-					AttachColumnFilterListeners(m);
-				}
 				ApplySchema();
-			}
 			else if (e.PropertyName == nameof(MetadataTablePageModel.ScrollToRow))
-			{
 				ApplyScrollTarget();
-			}
-		}
-
-		void OnColumnFilterChanged(object? sender, PropertyChangedEventArgs e)
-		{
-			if (e.PropertyName == nameof(ColumnFilter.Text))
-				itemsView?.Refresh();
-		}
-
-		void AttachColumnFilterListeners(MetadataTablePageModel model)
-		{
-			foreach (var f in model.ColumnFilters)
-				f.PropertyChanged += OnColumnFilterChanged;
 		}
 
-		void DetachColumnFilterListeners(MetadataTablePageModel model)
-		{
-			foreach (var f in model.ColumnFilters)
-				f.PropertyChanged -= OnColumnFilterChanged;
-		}
+		void OnAnyColumnFilterChanged() => itemsView?.Refresh();
 
 		void ApplySchema()
 		{