Fix threading issues when accessing AssemblyList.Assemblies.

ILSpy/AssemblyList.cs

@@ -41,8 +41,10 @@ namespace ICSharpCode.ILSpy
 		
 		/// <summary>
 		/// The assemblies in this list.
+		/// Needs locking for multi-threaded access!
+		/// Write accesses are allowed on the GUI thread only (but still need locking!)
 		/// </summary>
-		public readonly ObservableCollection<AssemblyTreeNode> Assemblies = new ObservableCollection<AssemblyTreeNode>();
+		internal readonly ObservableCollection<AssemblyTreeNode> assemblies = new ObservableCollection<AssemblyTreeNode>();
 		
 		/// <summary>
 		/// Dictionary for quickly finding types (used in hyperlink navigation)
@@ -52,7 +54,7 @@ namespace ICSharpCode.ILSpy
 		public AssemblyList(string listName)
 		{
 			this.listName = listName;
-			Assemblies.CollectionChanged += Assemblies_CollectionChanged;
+			assemblies.CollectionChanged += Assemblies_CollectionChanged;
 		}
 		
 		/// <summary>
@@ -67,6 +69,16 @@ namespace ICSharpCode.ILSpy
 			this.dirty = false; // OpenAssembly() sets dirty, so reset it afterwards
 		}
 		
+		/// <summary>
+		/// Gets the loaded assemblies. This method is thread-safe.
+		/// </summary>
+		public AssemblyTreeNode[] GetAssemblies()
+		{
+			lock (assemblies) {
+				return assemblies.ToArray();
+			}
+		}
+		
 		/// <summary>
 		/// Saves this assembly list to XML.
 		/// </summary>
@@ -75,7 +87,7 @@ namespace ICSharpCode.ILSpy
 			return new XElement(
 				"List",
 				new XAttribute("name", this.ListName),
-				Assemblies.Select(asm => new XElement("Assembly", asm.FileName))
+				assemblies.Select(asm => new XElement("Assembly", asm.FileName))
 			);
 		}
 		
@@ -215,13 +227,13 @@ namespace ICSharpCode.ILSpy
 			
 			file = Path.GetFullPath(file);
 			
-			foreach (AssemblyTreeNode node in this.Assemblies) {
+			foreach (AssemblyTreeNode node in this.assemblies) {
 				if (file.Equals(node.FileName, StringComparison.OrdinalIgnoreCase))
 					return node;
 			}
 			
 			var newNode = new AssemblyTreeNode(file, this);
-			this.Assemblies.Add(newNode);
+			this.assemblies.Add(newNode);
 			return newNode;
 		}
 	}

ILSpy/MainWindow.xaml.cs

@@ -93,7 +93,7 @@ namespace ICSharpCode.ILSpy
 			for (int i = 1; i < args.Length; i++) {
 				assemblyList.OpenAssembly(args[i]);
 			}
-			if (assemblyList.Assemblies.Count == 0)
+			if (assemblyList.GetAssemblies().Length == 0)
 				LoadInitialAssemblies();
 			
 			SharpTreeNode node = FindNodeByPath(sessionSettings.ActiveTreeViewPath, true);
@@ -139,7 +139,7 @@ namespace ICSharpCode.ILSpy
 			history.Clear();
 			this.assemblyList = assemblyList;
 			
-			assemblyList.Assemblies.CollectionChanged += assemblyList_Assemblies_CollectionChanged;
+			assemblyList.assemblies.CollectionChanged += assemblyList_Assemblies_CollectionChanged;
 			
 			assemblyListTreeNode = new AssemblyListTreeNode(assemblyList);
 			assemblyListTreeNode.FilterSettings = sessionSettings.FilterSettings.Clone();

ILSpy/TextView/DecompilerTextView.cs

@@ -358,7 +358,7 @@ namespace ICSharpCode.ILSpy.TextView
 			} else if (reference is EventReference) {
 				mainWindow.SelectNode(assemblyList.FindEventNode(((EventReference)reference).Resolve()));
 			} else if (reference is AssemblyDefinition) {
-				mainWindow.SelectNode(assemblyList.Assemblies.FirstOrDefault(node => node.AssemblyDefinition == reference));
+				mainWindow.SelectNode(assemblyList.GetAssemblies().FirstOrDefault(node => node.AssemblyDefinition == reference));
 			}
 		}
 		#endregion

ILSpy/TreeNodes/AssemblyListTreeNode.cs

@@ -38,7 +38,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		}
 		
 		public AssemblyListTreeNode(AssemblyList assemblyList)
-			: base(assemblyList.Assemblies)
+			: base(assemblyList.assemblies)
 		{
 			if (assemblyList == null)
 				throw new ArgumentNullException("assemblyList");
@@ -61,20 +61,22 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			if (files == null)
 				files = data.GetData(DataFormats.FileDrop) as string[];
 			if (files != null) {
-				var nodes = (from file in files
-				             where file != null
-				             select assemblyList.OpenAssembly(file) into node
-				             where node != null
-				             select node).Distinct().ToList();
-				foreach (AssemblyTreeNode node in nodes) {
-					int nodeIndex = this.Children.IndexOf(node);
-					if (nodeIndex < index)
-						index--;
-					this.Children.RemoveAt(nodeIndex);
-				}
-				nodes.Reverse();
-				foreach (AssemblyTreeNode node in nodes) {
-					this.Children.Insert(index, node);
+				lock (assemblyList.assemblies) {
+					var nodes = (from file in files
+					             where file != null
+					             select assemblyList.OpenAssembly(file) into node
+					             where node != null
+					             select node).Distinct().ToList();
+					foreach (AssemblyTreeNode node in nodes) {
+						int nodeIndex = assemblyList.assemblies.IndexOf(node);
+						if (nodeIndex < index)
+							index--;
+						assemblyList.assemblies.RemoveAt(nodeIndex);
+					}
+					nodes.Reverse();
+					foreach (AssemblyTreeNode node in nodes) {
+						assemblyList.assemblies.Insert(index, node);
+					}
 				}
 			}
 		}
@@ -85,7 +87,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		{
 			language.WriteCommentLine(output, "List: " + assemblyList.ListName);
 			output.WriteLine();
-			foreach (AssemblyTreeNode asm in assemblyList.Assemblies) {
+			foreach (AssemblyTreeNode asm in assemblyList.GetAssemblies()) {
 				language.WriteCommentLine(output, new string('-', 60));
 				output.WriteLine();
 				asm.Decompile(language, output, options);

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -25,7 +25,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
-
+using System.Windows.Threading;
 using ICSharpCode.Decompiler;
 using ICSharpCode.TreeView;
 using Mono.Cecil;
@@ -128,18 +128,6 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			}
 		}
 		
-		MenuItem CreateRemoveAssemblyItem()
-		{
-			MenuItem item = new MenuItem() {
-				Header = "Remove assembly",
-				Icon = new Image() { Source = Images.Delete }
-			};
-			
-			item.Click += delegate { Delete(); };
-			
-			return item;
-		}
-		
 		sealed class MyAssemblyResolver : IAssemblyResolver
 		{
 			readonly AssemblyTreeNode parent;
@@ -178,7 +166,13 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		{
 			// specific to AssemblyTreeNode
 			var menu = new ContextMenu();
-			menu.Items.Add(CreateRemoveAssemblyItem());
+			
+			MenuItem item = new MenuItem() {
+				Header = "Remove assembly",
+				Icon = new Image() { Source = Images.Delete }
+			};
+			item.Click += delegate { Delete(); };
+			menu.Items.Add(item);
 			
 			return menu;
 		}
@@ -229,7 +223,9 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		
 		public override void DeleteCore()
 		{
-			assemblyList.Assemblies.Remove(this);
+			lock (assemblyList.assemblies) {
+				assemblyList.assemblies.Remove(this);
+			}
 		}
 		
 		internal const string DataFormat = "ILSpyAssemblies";
@@ -243,11 +239,16 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		
 		public AssemblyTreeNode LookupReferencedAssembly(string fullName)
 		{
-			foreach (AssemblyTreeNode node in assemblyList.Assemblies) {
+			foreach (AssemblyTreeNode node in assemblyList.GetAssemblies()) {
 				if (node.AssemblyDefinition != null && fullName.Equals(node.AssemblyDefinition.FullName, StringComparison.OrdinalIgnoreCase))
 					return node;
 			}
 			
+			if (!App.Current.Dispatcher.CheckAccess()) {
+				// Call this method on the GUI thread.
+				return (AssemblyTreeNode)App.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Func<string, AssemblyTreeNode>(LookupReferencedAssembly), fullName);
+			}
+			
 			var name = AssemblyNameReference.Parse(fullName);
 			string file = GacInterop.FindAssemblyInNetGac(name);
 			if (file == null) {

ILSpy/TreeNodes/DerivedTypesTreeNode.cs

@@ -37,7 +37,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		protected override IEnumerable<ILSpyTreeNodeBase> FetchChildren(CancellationToken cancellationToken)
 		{
 			// FetchChildren() runs on the main thread; but the enumerator will be consumed on a background thread
-			var assemblies = list.Assemblies.Select(node => node.AssemblyDefinition).Where(asm => asm != null).ToArray();
+			var assemblies = list.GetAssemblies().Select(node => node.AssemblyDefinition).Where(asm => asm != null).ToArray();
 			return FindDerivedTypes(type, assemblies, cancellationToken);
 		}