Use VS MEF for the extensibility hosting.

This replaces the uses of ComposeParts() with explicit GetExports for those fields previously marked [Import] or [ImportMany] in non-MEF-part classes.

ILSpy/AboutPage.cs

@@ -81,7 +81,7 @@ namespace ICSharpCode.ILSpy
 					};
 				});
 			output.WriteLine();
-			foreach (var plugin in App.CompositionContainer.GetExportedValues<IAboutPageAddition>())
+			foreach (var plugin in App.ExportProvider.GetExportedValues<IAboutPageAddition>())
 				plugin.Write(output);
 			output.WriteLine();
 			using (Stream s = typeof(AboutPage).Assembly.GetManifestResourceStream(typeof(AboutPage), "README.txt")) {

ILSpy/App.xaml.cs

@@ -18,7 +18,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.ComponentModel.Composition.Hosting;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -32,6 +31,8 @@ using System.Windows.Threading;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.Options;
 
+using Microsoft.VisualStudio.Composition;
+
 namespace ICSharpCode.ILSpy
 {
 	/// <summary>
@@ -39,15 +40,18 @@ namespace ICSharpCode.ILSpy
 	/// </summary>
 	public partial class App : Application
 	{
-		static CompositionContainer compositionContainer;
-		
-		public static CompositionContainer CompositionContainer {
-			get { return compositionContainer; }
-		}
 		
 		internal static CommandLineArguments CommandLineArguments;
 
-		internal static IList<ExceptionData> StartupExceptions = new List<ExceptionData>();
+		static ExportProvider exportProvider;
+		
+		public static ExportProvider ExportProvider => exportProvider;
+
+		static IExportProviderFactory exportProviderFactory;
+		
+		public static IExportProviderFactory ExportProviderFactory => exportProviderFactory;
+		
+		internal static readonly IList<ExceptionData> StartupExceptions = new List<ExceptionData>();
 		
 		internal class ExceptionData
 		{
@@ -68,32 +72,52 @@ namespace ICSharpCode.ILSpy
 			}
 			InitializeComponent();
 			
-			var catalog = new AggregateCatalog();
-			catalog.Catalogs.Add(new AssemblyCatalog(typeof(App).Assembly));
-			// Don't use DirectoryCatalog, that causes problems if the plugins are from the Internet zone
-			// see http://stackoverflow.com/questions/8063841/mef-loading-plugins-from-a-network-shared-folder
-			string appPath = Path.GetDirectoryName(typeof(App).Module.FullyQualifiedName);
-			foreach (string plugin in Directory.GetFiles(appPath, "*.Plugin.dll")) {
-				string shortName = Path.GetFileNameWithoutExtension(plugin);
-				try {
-					var asm = Assembly.Load(shortName);
-					asm.GetTypes();
-					catalog.Catalogs.Add(new AssemblyCatalog(asm));
-				} catch (Exception ex) {
 			// Cannot show MessageBox here, because WPF would crash with a XamlParseException
 			// Remember and show exceptions in text output, once MainWindow is properly initialized
-					StartupExceptions.Add(new ExceptionData { Exception = ex, PluginName = shortName });
+			try {
+				// Set up VS MEF. For now, only do MEF1 part discovery, since that was in use before.
+				// To support both MEF1 and MEF2 parts, just change this to:
+				// var discovery = PartDiscovery.Combine(new AttributedPartDiscoveryV1(Resolver.DefaultInstance),
+				//                                       new AttributedPartDiscovery(Resolver.DefaultInstance));
+				var discovery = new AttributedPartDiscoveryV1(Resolver.DefaultInstance);
+				var catalog = ComposableCatalog.Create(Resolver.DefaultInstance);
+				var pluginDir = Path.GetDirectoryName(typeof(App).Module.FullyQualifiedName);
+				if (pluginDir != null) {
+					foreach (var plugin in Directory.GetFiles(pluginDir, "*.Plugin.dll")) {
+						var name = Path.GetFileNameWithoutExtension(plugin);
+						try {
+							var asm = Assembly.Load(name);
+							var parts = discovery.CreatePartsAsync(asm).Result;
+							catalog = catalog.AddParts(parts);
+						} catch (Exception ex) {
+							StartupExceptions.Add(new ExceptionData { Exception = ex, PluginName = name });
 						}
 					}
-			
-			compositionContainer = new CompositionContainer(catalog);
+				}
+				// Add the built-in parts
+				catalog = catalog.AddParts(discovery.CreatePartsAsync(Assembly.GetExecutingAssembly()).Result);
+				// If/When the project switches to .NET Standard/Core, this will be needed to allow metadata interfaces (as opposed
+				// to metadata classes). When running on .NET Framework, it's automatic.
+				//   catalog.WithDesktopSupport();
+				// If/When any part needs to import ICompositionService, this will be needed:
+				//   catalog.WithCompositionService();
+				var config = CompositionConfiguration.Create(catalog);
+				exportProviderFactory = config.CreateExportProviderFactory();
+				exportProvider = exportProviderFactory.CreateExportProvider();
+				// This throws exceptions for composition failures. Alternatively, the configuration's CompositionErrors property
+				// could be used to log the errors directly. Used at the end so that it does not prevent the export provider setup.
+				config.ThrowOnErrors();
+			}
+			catch (Exception ex) {
+				StartupExceptions.Add(new ExceptionData { Exception = ex });
+			}
 			
 			if (!System.Diagnostics.Debugger.IsAttached) {
 				AppDomain.CurrentDomain.UnhandledException += ShowErrorBox;
 				Dispatcher.CurrentDispatcher.UnhandledException += Dispatcher_UnhandledException;
 			}
 			TaskScheduler.UnobservedTaskException += DotNet40_UnobservedTaskException;
-			Languages.Initialize(compositionContainer);
+			Languages.Initialize(exportProvider);
 
 			EventManager.RegisterClassHandler(typeof(Window),
 			                                  Hyperlink.RequestNavigateEvent,

ILSpy/ContextMenuEntry.cs

@@ -149,21 +149,22 @@ namespace ICSharpCode.ILSpy
 		readonly SharpTreeView treeView;
 		readonly DecompilerTextView textView;
 		readonly ListBox listBox;
+		readonly Lazy<IContextMenuEntry, IContextMenuEntryMetadata>[] entries;
 		
-		[ImportMany(typeof(IContextMenuEntry))]
-		Lazy<IContextMenuEntry, IContextMenuEntryMetadata>[] entries = null;
+		private ContextMenuProvider()
+		{
+			entries = App.ExportProvider.GetExports<IContextMenuEntry, IContextMenuEntryMetadata>().ToArray();
+		}
 		
-		ContextMenuProvider(SharpTreeView treeView, DecompilerTextView textView = null)
+		ContextMenuProvider(SharpTreeView treeView, DecompilerTextView textView = null) : this()
 		{
 			this.treeView = treeView;
 			this.textView = textView;
-			App.CompositionContainer.ComposeParts(this);
 		}
 		
-		ContextMenuProvider(ListBox listBox)
+		ContextMenuProvider(ListBox listBox) : this()
 		{
 			this.listBox = listBox;
-			App.CompositionContainer.ComposeParts(this);
 		}
 		
 		void treeView_ContextMenuOpening(object sender, ContextMenuEventArgs e)

ILSpy/ILSpy.csproj

@@ -42,7 +42,6 @@
   <ItemGroup>
     <Reference Include="PresentationCore" />
     <Reference Include="PresentationFramework" />
-    <Reference Include="System.ComponentModel.Composition" />
     <Reference Include="System.IO.Compression" />
     <Reference Include="System.Windows.Forms" />
     <Reference Include="System.Xaml" />
@@ -51,6 +50,7 @@
 
   <ItemGroup>
     <PackageReference Include="AvalonEdit" Version="5.0.4" />
+    <PackageReference Include="Microsoft.VisualStudio.Composition" Version="15.5.23" />
   </ItemGroup>
 
   <ItemGroup>

ILSpy/Languages/CSharpLanguage.cs

@@ -390,7 +390,7 @@ namespace ICSharpCode.ILSpy
 					}
 					return new[] { Tuple.Create("EmbeddedResource", fileName) };
 				}
-				foreach (var handler in App.CompositionContainer.GetExportedValues<IResourceFileHandler>()) {
+				foreach (var handler in App.ExportProvider.GetExportedValues<IResourceFileHandler>()) {
 					if (handler.CanHandle(fileName, options)) {
 						entryStream.Position = 0;
 						return new[] { Tuple.Create(handler.EntryType, handler.WriteResourceToFile(assembly, fileName, entryStream, options)) };

ILSpy/Languages/Languages.cs

@@ -18,9 +18,10 @@
 
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.ComponentModel.Composition.Hosting;
 using System.Linq;
 
+using Microsoft.VisualStudio.Composition;
+
 namespace ICSharpCode.ILSpy
 {
 	public static class Languages
@@ -39,10 +40,10 @@ namespace ICSharpCode.ILSpy
 			get { return allLanguages; }
 		}
 
-		internal static void Initialize(CompositionContainer composition)
+		internal static void Initialize(ExportProvider ep)
 		{
 			List<Language> languages = new List<Language>();
-			languages.AddRange(composition.GetExportedValues<Language>());
+			languages.AddRange(ep.GetExportedValues<Language>());
 			languages.Sort((a, b) => a.Name.CompareTo(b.Name));
 			#if DEBUG
 			languages.AddRange(ILAstLanguage.GetDebugLanguages());

ILSpy/MainWindow.xaml.cs

@@ -20,7 +20,6 @@ using System;
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.ComponentModel;
-using System.ComponentModel.Composition;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -55,8 +54,7 @@ namespace ICSharpCode.ILSpy
 		AssemblyList assemblyList;
 		AssemblyListTreeNode assemblyListTreeNode;
 		
-		[Import]
-		DecompilerTextView decompilerTextView = null;
+		readonly DecompilerTextView decompilerTextView;
 		
 		static MainWindow instance;
 		
@@ -80,7 +78,7 @@ namespace ICSharpCode.ILSpy
 			this.DataContext = sessionSettings;
 			
 			InitializeComponent();
-			App.CompositionContainer.ComposeParts(this);
+			decompilerTextView = App.ExportProvider.GetExportedValue<DecompilerTextView>();
 			mainPane.Content = decompilerTextView;
 			
 			if (sessionSettings.SplitterPosition > 0 && sessionSettings.SplitterPosition < 1) {
@@ -105,13 +103,12 @@ namespace ICSharpCode.ILSpy
 		}
 		
 		#region Toolbar extensibility
-		[ImportMany("ToolbarCommand", typeof(ICommand))]
-		Lazy<ICommand, IToolbarCommandMetadata>[] toolbarCommands = null;
 		
 		void InitToolbar()
 		{
 			int navigationPos = 0;
 			int openPos = 1;
+			var toolbarCommands = App.ExportProvider.GetExports<ICommand, IToolbarCommandMetadata>("ToolbarCommand");
 			foreach (var commandGroup in toolbarCommands.OrderBy(c => c.Metadata.ToolbarOrder).GroupBy(c => c.Metadata.ToolbarCategory)) {
 				if (commandGroup.Key == "Navigation") {
 					foreach (var command in commandGroup) {
@@ -148,11 +145,10 @@ namespace ICSharpCode.ILSpy
 		#endregion
 		
 		#region Main Menu extensibility
-		[ImportMany("MainMenuCommand", typeof(ICommand))]
-		Lazy<ICommand, IMainMenuCommandMetadata>[] mainMenuCommands = null;
 		
 		void InitMainMenu()
 		{
+			var mainMenuCommands = App.ExportProvider.GetExports<ICommand, IMainMenuCommandMetadata>("MainMenuCommand");
 			foreach (var topLevelMenu in mainMenuCommands.OrderBy(c => c.Metadata.MenuOrder).GroupBy(c => c.Metadata.Menu)) {
 				var topLevelMenuItem = mainMenu.Items.OfType<MenuItem>().FirstOrDefault(m => (m.Header as string) == topLevelMenu.Key);
 				foreach (var category in topLevelMenu.GroupBy(c => c.Metadata.MenuCategory)) {

ILSpy/Options/OptionsDialog.xaml.cs

@@ -30,13 +30,17 @@ namespace ICSharpCode.ILSpy.Options
 	/// </summary>
 	public partial class OptionsDialog : Window
 	{
-		[ImportMany("OptionPages", typeof(UIElement), RequiredCreationPolicy = CreationPolicy.NonShared)]
-		Lazy<UIElement, IOptionsMetadata>[] optionPages = null;
+		
+		readonly Lazy<UIElement, IOptionsMetadata>[] optionPages;
 		
 		public OptionsDialog()
 		{
 			InitializeComponent();
-			App.CompositionContainer.ComposeParts(this);
+			// These used to have [ImportMany(..., RequiredCreationPolicy = CreationPolicy.NonShared)], so they use their own
+			// ExportProvider instance.
+			// FIXME: Ideally, the export provider should be disposed when it's no longer needed.
+			var ep = App.ExportProviderFactory.CreateExportProvider();
+			this.optionPages = ep.GetExports<UIElement, IOptionsMetadata>("OptionPages").ToArray();
 			ILSpySettings settings = ILSpySettings.Load();
 			foreach (var optionPage in optionPages.OrderBy(p => p.Metadata.Order)) {
 				TabItem tabItem = new TabItem();

ILSpy/TreeNodes/ResourceNodes/ResourceEntryNode.cs

@@ -61,7 +61,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		public static ILSpyTreeNode Create(string key, object data)
 		{
 			ILSpyTreeNode result = null;
-			foreach (var factory in App.CompositionContainer.GetExportedValues<IResourceNodeFactory>()) {
+			foreach (var factory in App.ExportProvider.GetExportedValues<IResourceNodeFactory>()) {
 				result = factory.CreateNode(key, data);
 				if (result != null)
 					return result;

ILSpy/TreeNodes/ResourceNodes/ResourceTreeNode.cs

@@ -122,7 +122,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		public static ILSpyTreeNode Create(Resource resource)
 		{
 			ILSpyTreeNode result = null;
-			foreach (var factory in App.CompositionContainer.GetExportedValues<IResourceNodeFactory>()) {
+			foreach (var factory in App.ExportProvider.GetExportedValues<IResourceNodeFactory>()) {
 				result = factory.CreateNode(resource);
 				if (result != null)
 					break;