Filter row above the metadata grid

FilterText on MetadataTablePageModel drives a case-insensitive Contains
predicate over each row's stringified property values; the view wraps
Items in a DataGridCollectionView so the filter applies without rebinding.

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

ILSpy.Tests/Metadata/MetadataFilterTests.cs

@@ -0,0 +1,118 @@
+// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Linq;
+using System.Threading.Tasks;
+
+using Avalonia.Headless.NUnit;
+
+using AwesomeAssertions;
+
+using ILSpy.AppEnv;
+using ILSpy.Metadata;
+using ILSpy.Metadata.CorTables;
+using ILSpy.TreeNodes;
+using ILSpy.ViewModels;
+using ILSpy.Views;
+
+using NUnit.Framework;
+
+namespace ICSharpCode.ILSpy.Tests.Metadata;
+
+[TestFixture]
+public class MetadataFilterTests
+{
+	sealed class SampleEntry
+	{
+		public int RID { get; set; }
+		public string Name { get; set; } = "";
+		public string Culture { get; set; } = "";
+	}
+
+	[Test]
+	public void MatchesFilter_Returns_True_For_Empty_Or_Null_Filter()
+	{
+		// An empty filter must show every row — the no-filter state is the identity case.
+		var entry = new SampleEntry { RID = 1, Name = "System.Runtime" };
+		MetadataTablePageModel.MatchesFilter(entry, null).Should().BeTrue();
+		MetadataTablePageModel.MatchesFilter(entry, "").Should().BeTrue();
+	}
+
+	[Test]
+	public void MatchesFilter_Returns_True_When_Any_Property_Contains_The_Substring_Case_Insensitively()
+	{
+		// Filter is a case-insensitive Contains over every property's stringified value, so
+		// "system" matches "System.Runtime" and "neutral" matches the Culture column.
+		var entry = new SampleEntry { RID = 1, Name = "System.Runtime", Culture = "neutral" };
+		MetadataTablePageModel.MatchesFilter(entry, "system").Should().BeTrue();
+		MetadataTablePageModel.MatchesFilter(entry, "RUNTIME").Should().BeTrue();
+		MetadataTablePageModel.MatchesFilter(entry, "neutral").Should().BeTrue();
+	}
+
+	[Test]
+	public void MatchesFilter_Returns_False_When_No_Property_Contains_The_Substring()
+	{
+		var entry = new SampleEntry { RID = 1, Name = "System.Runtime" };
+		MetadataTablePageModel.MatchesFilter(entry, "Foo").Should().BeFalse();
+	}
+
+	[Test]
+	public void MatchesFilter_Stringifies_Numeric_Values_So_Filter_Hits_Numeric_Columns()
+	{
+		// Without stringifying, filtering "42" against a numeric RID would silently miss.
+		var entry = new SampleEntry { RID = 42, Name = "X" };
+		MetadataTablePageModel.MatchesFilter(entry, "42").Should().BeTrue();
+	}
+
+	[AvaloniaTest]
+	public async Task FilterText_Reduces_Visible_Rows_To_Those_Whose_Property_Contains_The_Substring()
+	{
+		// Integration check: navigate to the TypeDef table (guaranteed populated for any
+		// loaded module) and confirm setting FilterText='System' shrinks the visible-row
+		// set, and clearing it restores the full set.
+
+		var window = AppComposition.Current.GetExport<MainWindow>();
+		window.Show();
+		var vm = (MainWindowViewModel)window.DataContext!;
+		await vm.AssemblyTreeModel.WaitForAssembliesAsync(minimumCount: 1);
+
+		var coreLibName = typeof(object).Assembly.GetName().Name!;
+		var assemblyNode = vm.AssemblyTreeModel.FindNode<AssemblyTreeNode>(coreLibName);
+		assemblyNode.EnsureLazyChildren();
+		var metadataNode = assemblyNode.Children.OfType<MetadataTreeNode>().Single();
+		metadataNode.EnsureLazyChildren();
+		var tablesNode = metadataNode.Children.OfType<MetadataTablesTreeNode>().Single();
+		tablesNode.EnsureLazyChildren();
+		var typeDefNode = tablesNode.Children.OfType<TypeDefTableTreeNode>().Single();
+
+		vm.AssemblyTreeModel.SelectNode(typeDefNode);
+		var tab = await vm.DockWorkspace.WaitForMetadataTabAsync();
+
+		var totalCount = tab.Items.Count;
+		totalCount.Should().BeGreaterThan(0);
+
+		tab.FilterText = "System";
+		var visible = tab.Items.Where(e => MetadataTablePageModel.MatchesFilter(e, tab.FilterText)).ToList();
+		visible.Should().NotBeEmpty("at least one TypeDef row should mention 'System'");
+		visible.Count.Should().BeLessThan(totalCount, "the filter must hide at least one row");
+
+		tab.FilterText = "";
+		var afterClear = tab.Items.Where(e => MetadataTablePageModel.MatchesFilter(e, tab.FilterText)).Count();
+		afterClear.Should().Be(totalCount);
+	}
+}

ILSpy/ViewModels/MetadataTablePageModel.cs

@@ -17,7 +17,9 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Reflection;
 
 using Avalonia.Controls;
 
@@ -47,6 +49,14 @@ namespace ILSpy.ViewModels
 		[ObservableProperty]
 		private int? scrollToRow;
 
+		/// <summary>
+		/// Free-text filter applied to the visible rows. Empty / null shows every row;
+		/// otherwise the view shows the rows where any property's stringified value contains
+		/// the filter (case-insensitive). Bound two-way to a TextBox above the grid.
+		/// </summary>
+		[ObservableProperty]
+		private string? filterText;
+
 		/// <summary>
 		/// Raised when the user clicks a hyperlink-styled token cell. The host (the dock
 		/// workspace) resolves the (row, columnName) pair to a metadata token and navigates
@@ -56,6 +66,34 @@ namespace ILSpy.ViewModels
 
 		internal void RaiseNavigateToCell(object row, string columnName)
 			=> NavigateToCellRequested?.Invoke(new MetadataCellNavigationEventArgs(row, columnName));
+
+		static readonly ConcurrentDictionary<Type, PropertyInfo[]> filterPropertyCache = new();
+
+		/// <summary>
+		/// Predicate used by both the view's <c>DataGridCollectionView.Filter</c> and tests:
+		/// returns <see langword="true"/> when <paramref name="filter"/> is empty or any
+		/// public instance property's stringified value on <paramref name="item"/> contains
+		/// the filter case-insensitively.
+		/// </summary>
+		public static bool MatchesFilter(object item, string? filter)
+		{
+			ArgumentNullException.ThrowIfNull(item);
+			if (string.IsNullOrEmpty(filter))
+				return true;
+			var props = filterPropertyCache.GetOrAdd(item.GetType(),
+				static t => t.GetProperties(BindingFlags.Public | BindingFlags.Instance));
+			foreach (var prop in props)
+			{
+				object? value;
+				try
+				{ value = prop.GetValue(item); }
+				catch { continue; }
+				var s = value?.ToString();
+				if (s is not null && s.Contains(filter, StringComparison.OrdinalIgnoreCase))
+					return true;
+			}
+			return false;
+		}
 	}
 
 	/// <summary>The (row, column) pair clicked in a token cell.</summary>

ILSpy/Views/MetadataTablePage.axaml

@@ -7,19 +7,27 @@
              x:Class="ILSpy.Views.MetadataTablePage"
              x:DataType="vm:MetadataTablePageModel">
 
-	<!-- ItemsSource and Columns are wired imperatively in code-behind so the (clear-cols /
-	     add-cols / set-items) sequence runs as a single transaction. Binding ItemsSource
-	     declaratively crashes the DataGrid's measure pass when the view is reused across
-	     content types whose schemas have a different column count, because Avalonia's
-	     binding-system rebind happens after the imperative column rewrite. -->
-	<DataGrid Name="Grid"
-	          CanUserResizeColumns="True"
-	          CanUserSortColumns="True"
-	          CanUserReorderColumns="False"
-	          IsReadOnly="True"
-	          GridLinesVisibility="None"
-	          HeadersVisibility="Column"
-	          SelectionMode="Single"
-	          AutoGenerateColumns="False" />
+	<DockPanel LastChildFill="True">
+		<TextBox Name="FilterBox"
+		         DockPanel.Dock="Top"
+		         PlaceholderText="Filter (case-insensitive substring match across columns)"
+		         Margin="4,4,4,2"
+		         Text="{Binding FilterText, Mode=TwoWay}" />
+
+		<!-- ItemsSource and Columns are wired imperatively in code-behind so the (clear-cols /
+		     add-cols / set-items) sequence runs as a single transaction. Binding ItemsSource
+		     declaratively crashes the DataGrid's measure pass when the view is reused across
+		     content types whose schemas have a different column count, because Avalonia's
+		     binding-system rebind happens after the imperative column rewrite. -->
+		<DataGrid Name="Grid"
+		          CanUserResizeColumns="True"
+		          CanUserSortColumns="True"
+		          CanUserReorderColumns="False"
+		          IsReadOnly="True"
+		          GridLinesVisibility="None"
+		          HeadersVisibility="Column"
+		          SelectionMode="Single"
+		          AutoGenerateColumns="False" />
+	</DockPanel>
 
 </UserControl>

ILSpy/Views/MetadataTablePage.axaml.cs

@@ -19,6 +19,7 @@
 using System;
 using System.ComponentModel;
 
+using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
 
@@ -35,6 +36,7 @@ namespace ILSpy.Views
 	public partial class MetadataTablePage : UserControl
 	{
 		MetadataTablePageModel? boundModel;
+		DataGridCollectionView? itemsView;
 
 		public MetadataTablePage()
 		{
@@ -60,6 +62,8 @@ namespace ILSpy.Views
 			if (e.PropertyName is nameof(MetadataTablePageModel.Columns)
 				or nameof(MetadataTablePageModel.Items))
 				ApplySchema();
+			else if (e.PropertyName == nameof(MetadataTablePageModel.FilterText))
+				itemsView?.Refresh();
 			else if (e.PropertyName == nameof(MetadataTablePageModel.ScrollToRow))
 				ApplyScrollTarget();
 		}
@@ -76,11 +80,15 @@ namespace ILSpy.Views
 			// the new schema has more columns than the old one.
 			grid.ItemsSource = Array.Empty<object>();
 			grid.Columns.Clear();
+			itemsView = null;
 			if (boundModel == null)
 				return;
 			foreach (var c in boundModel.Columns)
 				grid.Columns.Add(c);
-			grid.ItemsSource = boundModel.Items;
+			itemsView = new DataGridCollectionView(boundModel.Items) {
+				Filter = item => MetadataTablePageModel.MatchesFilter(item, boundModel?.FilterText),
+			};
+			grid.ItemsSource = itemsView;
 		}
 
 		void ApplyScrollTarget()