Work on designer extensibility framework.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@2224 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Configuration/AssemblyInfo.cs

@@ -7,6 +7,7 @@ using System.Resources;
 using System.Globalization;
 using System.Windows;
 using System.Runtime.InteropServices;
+using ICSharpCode.WpfDesign.Extensions;
 
 #endregion
 

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/TabItemClickableExtension.cs

@@ -0,0 +1,23 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using ICSharpCode.WpfDesign.Extensions;
+
+namespace ICSharpCode.WpfDesign.Designer.Extensions
+{
+	/// <summary>
+	/// Makes the TabItem clickable.
+	/// </summary>
+	[ExtensionFor(typeof(TabItem))]
+	public sealed class TabItemClickableExtension : BehaviorExtension
+	{
+		
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Linq.cs

@@ -10,6 +10,7 @@ using System.Collections.Generic;
 
 namespace ICSharpCode.WpfDesign.Designer
 {
+	// Static helpers that should become extension methods in the future
 	static class Linq
 	{
 		public static T[] ToArray<T>(ICollection<T> collection)

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Services/ToolService.cs

@@ -50,11 +50,11 @@ namespace ICSharpCode.WpfDesign.Designer.Services
 		public void OnMouseDown(IDesignPanel designPanel, MouseButtonEventArgs e)
 		{
 			e.Handled = true;
-			new SelectionTask().Start(designPanel, e);
+			new SelectionGesture().Start(designPanel, e);
 		}
 	}
 	
-	abstract class TaskBase
+	abstract class MouseGestureBase
 	{
 		protected IDesignPanel designPanel;
 		bool isStarted;
@@ -120,7 +120,7 @@ namespace ICSharpCode.WpfDesign.Designer.Services
 		protected virtual void OnStopped() {}
 	}
 	
-	sealed class SelectionTask : TaskBase
+	sealed class SelectionGesture : MouseGestureBase
 	{
 		protected override void OnStarted(MouseButtonEventArgs e)
 		{

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/WpfDesign.Designer.csproj

@@ -58,7 +58,7 @@
     <Compile Include="Configuration\AssemblyInfo.cs" />
     <Compile Include="Controls\SingleVisualChildElement.cs" />
     <Compile Include="DesignPanel.cs" />
-    <Compile Include="HashSet.cs" />
+    <Compile Include="Extensions\TabItemClickableExtension.cs" />
     <Compile Include="Linq.cs" />
     <Compile Include="ServiceRequiredException.cs" />
     <Compile Include="Services\SelectionService.cs" />
@@ -72,6 +72,7 @@
   <ItemGroup>
     <Folder Include="Configuration" />
     <Folder Include="Controls" />
+    <Folder Include="Extensions" />
     <Folder Include="Xaml" />
     <Folder Include="Services" />
     <ProjectReference Include="..\..\WpfDesign.XamlDom\Project\WpfDesign.XamlDom.csproj">

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Xaml/XamlDesignContext.cs

@@ -30,6 +30,9 @@ namespace ICSharpCode.WpfDesign.Designer.Xaml
 			_componentService = new XamlComponentService(this);
 			this.Services.AddService(typeof(IComponentService), _componentService);
 			
+			// register extensions from this assembly:
+			this.Services.ExtensionManager.RegisterAssembly(typeof(XamlDesignContext).Assembly);
+			
 			_rootItem = _componentService.RegisterXamlComponentRecursive(doc.RootElement);
 		}
 		

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/DesignContext.cs

@@ -18,6 +18,14 @@ namespace ICSharpCode.WpfDesign
 	{
 		readonly ServiceContainer _services = new ServiceContainer();
 		
+		/// <summary>
+		/// Creates a new DesignContext instance.
+		/// </summary>
+		protected DesignContext()
+		{
+			_services.AddService(typeof(Extensions.ExtensionManager), new Extensions.ExtensionManager(this));
+		}
+		
 		/// <summary>
 		/// Gets the <see cref="ServiceContainer"/>.
 		/// </summary>

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/DesignItem.cs

@@ -9,6 +9,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Windows;
+using ICSharpCode.WpfDesign.Extensions;
 
 namespace ICSharpCode.WpfDesign
 {
@@ -16,11 +17,6 @@ namespace ICSharpCode.WpfDesign
 	/// The DesignItem connects a component with the service system and the designers.
 	/// Equivalent to Cider's ModelItem.
 	/// </summary>
-	/// <remarks>
-	/// About the Cider extension system:
-	/// http://blogs.msdn.com/jnak/archive/2006/04/24/580393.aspx
-	/// http://blogs.msdn.com/jnak/archive/2006/08/04/687166.aspx
-	/// </remarks>
 	public abstract class DesignItem
 	{
 		/// <summary>
@@ -45,5 +41,72 @@ namespace ICSharpCode.WpfDesign
 			[DebuggerStepThrough]
 			get { return this.Context.Services; }
 		}
+		
+		#region Extensions support
+		private struct ExtensionEntry
+		{
+			internal readonly Extension Extension;
+			internal readonly ExtensionServer Server;
+			
+			public ExtensionEntry(Extension extension, ExtensionServer server)
+			{
+				this.Extension = extension;
+				this.Server = server;
+			}
+		}
+		
+		ExtensionServer[] _extensionServers;
+		bool[] _extensionServerIsApplied;
+		
+		List<ExtensionEntry> _extensions = new List<ExtensionEntry>();
+		
+		/// <summary>
+		/// Gets the extensions registered for this DesignItem.
+		/// </summary>
+		public IEnumerable<Extension> Extensions {
+			get {
+				foreach (ExtensionEntry entry in _extensions) {
+					yield return entry.Extension;
+				}
+			}
+		}
+		
+		internal void SetExtensionServers(ExtensionServer[] extensionServers)
+		{
+			Debug.Assert(_extensionServers == null);
+			Debug.Assert(extensionServers != null);
+			
+			_extensionServers = extensionServers;
+			_extensionServerIsApplied = new bool[extensionServers.Length];
+		}
+		
+		internal void ApplyExtensions(ExtensionManager extensionManager)
+		{
+			Debug.Assert(_extensionServers != null);
+			for (int i = 0; i < _extensionServers.Length; i++) {
+				bool shouldApply = _extensionServers[i].ShouldApplyExtensions(this);
+				if (shouldApply != _extensionServerIsApplied[i]) {
+					ExtensionServer server = _extensionServers[i];
+					if (shouldApply) {
+						// add extensions
+						foreach (Extension ext in extensionManager.CreateExtensions(server, this)) {
+							_extensions.Add(new ExtensionEntry(ext, server));
+						}
+					} else {
+						// remove extensions
+						_extensions.RemoveAll(
+							delegate (ExtensionEntry entry) {
+								if (entry.Server == server) {
+									server.RemoveExtension(entry.Extension);
+									return true;
+								} else {
+									return false;
+								}
+							});
+					}
+				}
+			}
+		}
+		#endregion
 	}
 }

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/BehaviorExtension.cs

@@ -0,0 +1,79 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+
+namespace ICSharpCode.WpfDesign.Extensions
+{
+	/// <summary>
+	/// Base class for extensions that provide a behavior interface for the designed item.
+	/// These extensions are always loaded. They must have an parameter-less constructor.
+	/// </summary>
+	[ExtensionServer(typeof(BehaviorExtension.BehaviorExtensionServer))]
+	public abstract class BehaviorExtension : Extension
+	{
+		DesignItem _extendedItem;
+		
+		/// <summary>
+		/// Gets the item that is being extended by the BehaviorExtension.
+		/// </summary>
+		public DesignItem ExtendedItem {
+			get {
+				if (_extendedItem == null)
+					throw new InvalidOperationException("Cannot access BehaviorExtension.ExtendedItem: " +
+					                                    "The property is not initialized yet. Please move initialization logic " +
+					                                    "that depends on ExtendedItem into the OnInitialized method.");
+				return _extendedItem;
+			}
+		}
+		
+		/// <summary>
+		/// Gets the design context of the extended item. "Context" is equivalent to "ExtendedItem.Context".
+		/// </summary>
+		public DesignContext Context {
+			get {
+				return this.ExtendedItem.Context;
+			}
+		}
+		
+		/// <summary>
+		/// Gets the service container of the extended item. "Services" is equivalent to "ExtendedItem.Services".
+		/// </summary>
+		public ServiceContainer Services {
+			get {
+				return this.ExtendedItem.Services;
+			}
+		}
+		
+		/// <summary>
+		/// Is called after the ExtendedItem was set.
+		/// </summary>
+		protected virtual void OnInitialized()
+		{
+		}
+		
+		sealed class BehaviorExtensionServer : ExtensionServer
+		{
+			public override bool ShouldApplyExtensions(DesignItem extendedItem)
+			{
+				return true;
+			}
+			
+			public override Extension CreateExtension(Type extensionType, DesignItem extendedItem)
+			{
+				BehaviorExtension ext = (BehaviorExtension)Activator.CreateInstance(extensionType);
+				ext._extendedItem = extendedItem;
+				ext.OnInitialized();
+				return ext;
+			}
+			
+			public override void RemoveExtension(Extension extension)
+			{
+			}
+		}
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/Extension.cs

@@ -6,12 +6,19 @@
 // </file>
 
 using System;
+using System.Diagnostics;
 
 namespace ICSharpCode.WpfDesign.Extensions
 {
 	/// <summary>
 	/// Base class for all Extensions.
 	/// </summary>
+	/// <remarks>
+	/// The class design in the ICSharpCode.WpfDesign.Extensions namespace was made to match that of Cider
+	/// as described in the blog posts:
+	/// http://blogs.msdn.com/jnak/archive/2006/04/24/580393.aspx
+	/// http://blogs.msdn.com/jnak/archive/2006/08/04/687166.aspx
+	/// </remarks>
 	public abstract class Extension
 	{
 	}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/ExtensionForAttribute.cs

@@ -0,0 +1,56 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+
+namespace ICSharpCode.WpfDesign.Extensions
+{
+	/// <summary>
+	/// Attribute to specify that the decorated class is a WPF extension for the specified item type.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Class, AllowMultiple=true, Inherited=false)]
+	public sealed class ExtensionForAttribute : Attribute
+	{
+		Type _designedItemType;
+		Type _overrideExtension;
+		
+		/// <summary>
+		/// Gets the type of the item that is designed using this extension.
+		/// </summary>
+		public Type DesignedItemType {
+			get { return _designedItemType; }
+		}
+		
+		/// <summary>
+		/// Gets/Sets the type of another extension that this extension is overriding.
+		/// </summary>
+		public Type OverrideExtension {
+			get { return _overrideExtension; }
+			set {
+				_overrideExtension = value;
+				if (value != null) {
+					if (!typeof(Extension).IsAssignableFrom(value)) {
+						throw new ArgumentException("OverrideExtension must specify the type of an Extension.");
+					}
+				}
+			}
+		}
+		
+		/// <summary>
+		/// Create a new ExtensionForAttribute that specifies that the decorated class
+		/// is a WPF extension for the specified item type.
+		/// </summary>
+		public ExtensionForAttribute(Type designedItemType)
+		{
+			if (designedItemType == null)
+				throw new ArgumentNullException("designedItemType");
+			if (!designedItemType.IsClass)
+				throw new ArgumentException("designedItemType must be a class");
+			_designedItemType = designedItemType;
+		}
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/ExtensionManager.cs

@@ -0,0 +1,190 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Diagnostics;
+using System.Collections.Generic;
+using System.Reflection;
+
+namespace ICSharpCode.WpfDesign.Extensions
+{
+	/// <summary>
+	/// Manages extension creation for a design context.
+	/// </summary>
+	public sealed class ExtensionManager
+	{
+		readonly DesignContext _context;
+		
+		internal ExtensionManager(DesignContext context)
+		{
+			Debug.Assert(context != null);
+			this._context = context;
+			
+			context.Services.Subscribe<IComponentService>(
+				delegate(IComponentService componentService) {
+					componentService.ComponentRegistered += OnComponentRegistered;
+				});
+		}
+		
+		void OnComponentRegistered(object sender, DesignItemEventArgs e)
+		{
+			e.Item.SetExtensionServers(GetExtensionServersForItem(e.Item));
+			e.Item.ApplyExtensions(this);
+		}
+		
+		#region Manage ExtensionEntries
+		sealed class ExtensionEntry
+		{
+			internal readonly Type ExtensionType;
+			internal readonly ExtensionServer Server;
+			internal readonly Type OverriddenExtensionType;
+			
+			public ExtensionEntry(Type extensionType, ExtensionServer server, Type overriddenExtensionType)
+			{
+				this.ExtensionType = extensionType;
+				this.Server = server;
+				this.OverriddenExtensionType = overriddenExtensionType;
+			}
+		}
+		
+		Dictionary<Type, List<ExtensionEntry>> _extensions = new Dictionary<Type, List<ExtensionEntry>>();
+		
+		void AddExtensionEntry(Type extendedItemType, ExtensionEntry entry)
+		{
+			List<ExtensionEntry> list;
+			if (!_extensions.TryGetValue(extendedItemType, out list)) {
+				list = _extensions[extendedItemType] = new List<ExtensionEntry>();
+			}
+			list.Add(entry);
+		}
+		
+		List<ExtensionEntry> GetExtensionEntries(Type extendedItemType)
+		{
+			List<ExtensionEntry> result;
+			if (extendedItemType.BaseType != null)
+				result = GetExtensionEntries(extendedItemType.BaseType);
+			else
+				result = new List<ExtensionEntry>();
+			
+			List<ExtensionEntry> list;
+			if (_extensions.TryGetValue(extendedItemType, out list)) {
+				foreach (ExtensionEntry entry in list) {
+					if (entry.OverriddenExtensionType != null) {
+						result.RemoveAll(delegate(ExtensionEntry oldEntry) {
+						                 	return oldEntry.ExtensionType == entry.OverriddenExtensionType;
+						                 });
+					}
+					result.Add(entry);
+				}
+			}
+			return result;
+		}
+		#endregion
+		
+		#region Create Extensions
+		static readonly ExtensionEntry[] emptyExtensionEntryArray = new ExtensionEntry[0];
+		
+		IEnumerable<ExtensionEntry> GetExtensionEntries(DesignItem extendedItem)
+		{
+			if (extendedItem.Component == null)
+				return emptyExtensionEntryArray;
+			else
+				return GetExtensionEntries(extendedItem.Component.GetType());
+		}
+		
+		ExtensionServer[] GetExtensionServersForItem(DesignItem item)
+		{
+			Debug.Assert(item != null);
+			
+			HashSet<ExtensionServer> servers = new HashSet<ExtensionServer>();
+			foreach (ExtensionEntry entry in GetExtensionEntries(item)) {
+				servers.Add(entry.Server);
+			}
+			return Linq.ToArray(servers);
+		}
+		
+		internal IEnumerable<Extension> CreateExtensions(ExtensionServer server, DesignItem item)
+		{
+			Debug.Assert(server != null);
+			Debug.Assert(item != null);
+			
+			foreach (ExtensionEntry entry in GetExtensionEntries(item)) {
+				if (entry.Server == server) {
+					yield return server.CreateExtension(entry.ExtensionType, item);
+				}
+			}
+		}
+		#endregion
+		
+		#region RegisterAssembly
+		HashSet<Assembly> _registeredAssemblies = new HashSet<Assembly>();
+		
+		/// <summary>
+		/// Registers extensions from the specified assembly.
+		/// </summary>
+		public void RegisterAssembly(Assembly assembly)
+		{
+			if (assembly == null)
+				throw new ArgumentNullException("assembly");
+			
+//			object[] assemblyAttributes = assembly.GetCustomAttributes(typeof(IsWpfDesignerAssemblyAttribute), false);
+//			if (assemblyAttributes.Length == 0)
+//				return;
+			
+			if (!_registeredAssemblies.Add(assembly)) {
+				// the assembly already is registered, don't try to register it again.
+				return;
+			}
+			
+//			IsWpfDesignerAssemblyAttribute isWpfDesignerAssembly = (IsWpfDesignerAssemblyAttribute)assemblyAttributes[0];
+//			foreach (Type type in isWpfDesignerAssembly.UsePrivateReflection ? assembly.GetTypes() : assembly.GetExportedTypes()) {
+			foreach (Type type in assembly.GetTypes()) {
+				object[] extensionForAttributes = type.GetCustomAttributes(typeof(ExtensionForAttribute), false);
+				if (extensionForAttributes.Length == 0)
+					continue;
+				
+				foreach (ExtensionForAttribute designerFor in extensionForAttributes) {
+					ExtensionServer server = GetServerForExtension(type);
+					AddExtensionEntry(designerFor.DesignedItemType, new ExtensionEntry(type, server, designerFor.OverrideExtension));
+				}
+			}
+		}
+		#endregion
+		
+		#region Extension Server Creation
+		// extension server type => extension server instance
+		Dictionary<Type, ExtensionServer> _extensionServers = new Dictionary<Type, ExtensionServer>();
+		
+		ExtensionServer GetServerForExtension(Type extensionType)
+		{
+			Debug.Assert(extensionType != null);
+			
+			foreach (ExtensionServerAttribute esa in extensionType.GetCustomAttributes(typeof(ExtensionServerAttribute), true)) {
+				return GetExtensionServer(esa);
+			}
+			throw new DesignerException("Extension types must have a [ExtensionServer] attribute.");
+		}
+		
+		/// <summary>
+		/// Gets the extension server for the specified extension server attribute.
+		/// </summary>
+		public ExtensionServer GetExtensionServer(ExtensionServerAttribute attribute)
+		{
+			Type extensionServerType = attribute.ExtensionServerType;
+			
+			ExtensionServer server;
+			if (_extensionServers.TryGetValue(extensionServerType, out server))
+				return server;
+			
+			server = (ExtensionServer)Activator.CreateInstance(extensionServerType);
+			server.InitializeExtensionServer(_context);
+			_extensionServers[extensionServerType] = server;
+			return server;
+		}
+		#endregion
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/ExtensionServer.cs

@@ -0,0 +1,78 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Diagnostics;
+
+namespace ICSharpCode.WpfDesign.Extensions
+{
+	/// <summary>
+	/// An ExtensionServer manages a creating and removing extensions of the specific extension type.
+	/// For a given DesignContext, a ExtensionServer is created only once.
+	/// The ExtensionServer can handle events raised by services without having to unregister its events
+	/// handlers because the ExtensionServer runs for the lifetime of the DesignContext.
+	/// </summary>
+	public abstract class ExtensionServer
+	{
+		DesignContext _context;
+		
+		/// <summary>
+		/// Gets the context this extension server was created for.
+		/// </summary>
+		public DesignContext Context {
+			[DebuggerStepThrough]
+			get {
+				if (_context == null)
+					throw new InvalidOperationException("Cannot access ExtensionServer.Context: " +
+					                                    "The property is not initialized yet. Please move initialization logic " +
+					                                    "that depends on Context into the OnInitialized method.");
+				return _context;
+			}
+		}
+		
+		/// <summary>
+		/// Gets the service container of the current context. "x.Services" is equivalent to "x.Context.Services".
+		/// </summary>
+		public ServiceContainer Services {
+			[DebuggerStepThrough]
+			get { return this.Context.Services; }
+		}
+		
+		internal void InitializeExtensionServer(DesignContext context)
+		{
+			Debug.Assert(this._context == null);
+			Debug.Assert(context != null);
+			this._context = context;
+			OnInitialized();
+		}
+		
+		/// <summary>
+		/// Is called after the extension server is initialized and the <see cref="Context"/> property has been set.
+		/// </summary>
+		protected virtual void OnInitialized()
+		{
+		}
+		
+		/// <summary>
+		/// Gets if the extension manager should apply the extensions from this server to the specified item.
+		/// Is called by the ExtensionManager.
+		/// </summary>
+		public abstract bool ShouldApplyExtensions(DesignItem extendedItem);
+		
+		/// <summary>
+		/// Create an extension of the specified type.
+		/// Is called by the ExtensionManager.
+		/// </summary>
+		public abstract Extension CreateExtension(Type extensionType, DesignItem extendedItem);
+		
+		/// <summary>
+		/// This method is called before an extension is removed from its DesignItem because it should not be applied anymore.
+		/// Is called by the ExtensionManager.
+		/// </summary>
+		public abstract void RemoveExtension(Extension extension);
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Extensions/ExtensionServerAttribute.cs

@@ -0,0 +1,42 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+
+namespace ICSharpCode.WpfDesign.Extensions
+{
+	/// <summary>
+	/// Attribute to specify that the decorated class is an extension using the specified extension server.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Class, AllowMultiple=false, Inherited=true)]
+	public sealed class ExtensionServerAttribute : Attribute
+	{
+		Type _extensionServerType;
+		
+		/// <summary>
+		/// Gets the type of the item that is designed using this extension.
+		/// </summary>
+		public Type ExtensionServerType {
+			get { return _extensionServerType; }
+		}
+		
+		/// <summary>
+		/// Create a new ExtensionServerAttribute that specifies that the decorated extension
+		/// uses the specified extension server.
+		/// </summary>
+		public ExtensionServerAttribute(Type extensionServerType)
+		{
+			if (extensionServerType == null)
+				throw new ArgumentNullException("extensionServerType");
+			if (!typeof(ExtensionServer).IsAssignableFrom(extensionServerType))
+				throw new ArgumentException("extensionServerType must derive from ExtensionServer");
+			if (extensionServerType.GetConstructor(new Type[0]) == null)
+				throw new ArgumentException("extensionServerType must have a parameter-less constructor");
+			_extensionServerType = extensionServerType;
+		}
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/HashSet.cs

@@ -11,7 +11,7 @@ using System.Text;
 using System.Collections;
 using System.Collections.Specialized;
 
-namespace ICSharpCode.WpfDesign.Designer
+namespace ICSharpCode.WpfDesign
 {
 	/// <summary>
 	/// Represents a set of items. The set does not preserve the order of items and does not allow items to
@@ -19,12 +19,16 @@ namespace ICSharpCode.WpfDesign.Designer
 	/// It supports collection change notifications and is cloned by sharing the underlying
 	/// data structure and delaying the actual copy until the next change.
 	/// </summary>
-	sealed class HashSet<T> : ICollection<T>, ICollection, ICloneable, INotifyCollectionChanged
+	[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
+	public sealed class HashSet<T> : ICollection<T>, ICollection, ICloneable, INotifyCollectionChanged
 		where T : class
 	{
 		Dictionary<T, object> _dict;
 		bool _copyOnWrite;
 		
+		/// <summary>
+		/// This event is raised whenever the collection changes.
+		/// </summary>
 		public event NotifyCollectionChangedEventHandler CollectionChanged;
 		
 		/// <summary>
@@ -66,6 +70,9 @@ namespace ICSharpCode.WpfDesign.Designer
 			}
 		}
 		
+		/// <summary>
+		/// Adds a list of items to the set. This is equivalent to calling <see cref="Add"/> for each item in <paramref name="items"/>.
+		/// </summary>
 		public void AddRange(IEnumerable<T> items)
 		{
 			foreach (T item in items) {
@@ -147,6 +154,9 @@ namespace ICSharpCode.WpfDesign.Designer
 		}
 
 		#region IEnumerable Members
+		/// <summary>
+		/// Gets an enumerator to enumerate the items in the set.
+		/// </summary>
 		public IEnumerator<T> GetEnumerator()
 		{
 			return _dict.Keys.GetEnumerator();

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/Linq.cs

@@ -0,0 +1,23 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.WpfDesign
+{
+	// Static helpers that should become extension methods in the future
+	static class Linq
+	{
+		public static T[] ToArray<T>(ICollection<T> collection)
+		{
+			T[] arr = new T[collection.Count];
+			collection.CopyTo(arr, 0);
+			return arr;
+		}
+	}
+}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/ServiceContainer.cs

@@ -18,7 +18,8 @@ namespace ICSharpCode.WpfDesign
 	/// </summary>
 	public sealed class ServiceContainer : IServiceProvider
 	{
-		Dictionary<Type, object> _services = new Dictionary<Type, object>();
+		readonly Dictionary<Type, object> _services = new Dictionary<Type, object>();
+		readonly Dictionary<Type, Delegate> _waitingSubscribers = new Dictionary<Type, Delegate>();
 		
 		/// <summary>
 		/// Adds a new service to the container.
@@ -37,6 +38,12 @@ namespace ICSharpCode.WpfDesign
 				throw new ArgumentNullException("serviceInstance");
 			
 			_services.Add(serviceInterface, serviceInstance);
+			
+			Delegate subscriber;
+			if (_waitingSubscribers.TryGetValue(serviceInterface, out subscriber)) {
+				_waitingSubscribers.Remove(serviceInterface);
+				subscriber.DynamicInvoke(serviceInstance);
+			}
 		}
 		
 		/// <summary>
@@ -50,7 +57,7 @@ namespace ICSharpCode.WpfDesign
 		}
 		
 		/// <summary>
-		/// Gets the service object of the specified type.
+		/// Gets the service object of the type T.
 		/// </summary>
 		[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
 		public T GetService<T>() where T : class
@@ -58,7 +65,28 @@ namespace ICSharpCode.WpfDesign
 			return (T)GetService(typeof(T));
 		}
 		
-		T GetServiceChecked<T>() where T : class
+		/// <summary>
+		/// Subscribes to the service of type T.
+		/// serviceAvailableAction will be called after the service gets available. If the service is already available,
+		/// the action will be called immediately.
+		/// </summary>
+		public void Subscribe<T>(Action<T> serviceAvailableAction) where T : class
+		{
+			T service = GetService<T>();
+			if (service != null) {
+				serviceAvailableAction(service);
+			} else {
+				Type serviceInterface = typeof(T);
+				Delegate existingSubscriber;
+				if (_waitingSubscribers.TryGetValue(serviceInterface, out existingSubscriber)) {
+					_waitingSubscribers[serviceInterface] = Delegate.Combine(existingSubscriber, serviceAvailableAction);
+				} else {
+					_waitingSubscribers[serviceInterface] = serviceAvailableAction;
+				}
+			}
+		}
+		
+		T GetServiceOrThrowException<T>() where T : class
 		{
 			T service = (T)GetService(typeof(T));
 			if (service == null) {
@@ -69,31 +97,41 @@ namespace ICSharpCode.WpfDesign
 		
 		/// <summary>
 		/// Gets the <see cref="ISelectionService"/>.
-		/// This service is guaranteed to always exist -> this property will never return null.
+		/// Throws an exception if the service is not found.
 		/// </summary>
 		public ISelectionService Selection {
 			get {
-				return GetServiceChecked<ISelectionService>();
+				return GetServiceOrThrowException<ISelectionService>();
 			}
 		}
 		
 		/// <summary>
 		/// Gets the <see cref="IToolService"/>.
-		/// This service is guaranteed to always exist -> this property will never return null.
+		/// Throws an exception if the service is not found.
 		/// </summary>
 		public IToolService Tool {
 			get {
-				return GetServiceChecked<IToolService>();
+				return GetServiceOrThrowException<IToolService>();
 			}
 		}
 		
 		/// <summary>
 		/// Gets the <see cref="IComponentService"/>.
-		/// This service is guaranteed to always exist -> this property will never return null.
+		/// Throws an exception if the service is not found.
 		/// </summary>
 		public IComponentService Component {
 			get {
-				return GetServiceChecked<IComponentService>();
+				return GetServiceOrThrowException<IComponentService>();
+			}
+		}
+		
+		/// <summary>
+		/// Gets the <see cref="ExtensionManager"/>.
+		/// Throws an exception if the service is not found.
+		/// </summary>
+		public Extensions.ExtensionManager ExtensionManager {
+			get {
+				return GetServiceOrThrowException<Extensions.ExtensionManager>();
 			}
 		}
 	}

src/AddIns/DisplayBindings/WpfDesign/WpfDesign/Project/WpfDesign.csproj

@@ -16,6 +16,8 @@
     <DelaySign>False</DelaySign>
     <AssemblyOriginatorKeyMode>File</AssemblyOriginatorKeyMode>
     <OutputPath>..\..\..\..\..\..\AddIns\AddIns\DisplayBindings\WpfDesign\</OutputPath>
+    <RunCodeAnalysis>False</RunCodeAnalysis>
+    <CodeAnalysisRules>-Microsoft.Globalization#CA1303</CodeAnalysisRules>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
     <DebugSymbols>true</DebugSymbols>
@@ -59,7 +61,14 @@
     <Compile Include="EventArgs.cs" />
     <Compile Include="Configuration\AssemblyInfo.cs" />
     <Compile Include="DesignerException.cs" />
+    <Compile Include="Extensions\BehaviorExtension.cs" />
     <Compile Include="Extensions\Extension.cs" />
+    <Compile Include="Extensions\ExtensionForAttribute.cs" />
+    <Compile Include="Extensions\ExtensionManager.cs" />
+    <Compile Include="Extensions\ExtensionServer.cs" />
+    <Compile Include="Extensions\ExtensionServerAttribute.cs" />
+    <Compile Include="HashSet.cs" />
+    <Compile Include="Linq.cs" />
     <Compile Include="ServiceContainer.cs" />
     <Compile Include="DesignItem.cs" />
     <Compile Include="Services.cs" />