Avoid using element syntax for content properties when doing so can lead to problems with the {Binding} markup extension. Closes #14.

ILSpy/BamlDecompiler.cs

@@ -14,6 +14,9 @@ using System.Xml.Linq;
 using ICSharpCode.AvalonEdit.Highlighting;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
+using System.Diagnostics;
+using System.Collections;
+using System.Collections.Generic;
 
 namespace ICSharpCode.ILSpy.Baml
 {
@@ -24,47 +27,239 @@ namespace ICSharpCode.ILSpy.Baml
 		{
 		}
 		
-		public string DecompileBaml(MemoryStream bamlCode, string containingAssemblyFile)
+		abstract class XamlNode
 		{
-			bamlCode.Position = 0;
-			TextWriter w = new StringWriter();
+			public readonly List<XamlNode> Children = new List<XamlNode>();
 			
-			Assembly assembly = Assembly.LoadFile(containingAssemblyFile);
+			public abstract void WriteTo(XamlWriter writer);
+		}
+
+		[Conditional("DEBUG")]
+		static void Log(string format, params object[] args)
+		{
+			//Debug.WriteLine(format, args);
+		}
+		
+		sealed class XamlObjectNode : XamlNode
+		{
+			public readonly XamlType Type;
 			
-			Baml2006Reader reader = new Baml2006Reader(bamlCode, new XamlReaderSettings() { ValuesMustBeString = true, LocalAssembly = assembly });
-			XDocument doc = new XDocument();
-			XamlXmlWriter writer = new XamlXmlWriter(doc.CreateWriter(), reader.SchemaContext);
+			public XamlObjectNode(XamlType type)
+			{
+				this.Type = type;
+			}
+			
+			public override void WriteTo(XamlWriter writer)
+			{
+				Log("StartObject {0}", this.Type);
+				writer.WriteStartObject(this.Type);
+				Debug.Indent();
+				foreach (XamlNode node in this.Children)
+					node.WriteTo(writer);
+				Debug.Unindent();
+				Log("EndObject");
+				writer.WriteEndObject();
+			}
+		}
+		
+		sealed class XamlGetObjectNode : XamlNode
+		{
+			public override void WriteTo(XamlWriter writer)
+			{
+				Log("GetObject");
+				writer.WriteGetObject();
+				Debug.Indent();
+				foreach (XamlNode node in this.Children)
+					node.WriteTo(writer);
+				Debug.Unindent();
+				Log("EndObject");
+				writer.WriteEndObject();
+			}
+		}
+		
+		sealed class XamlMemberNode : XamlNode
+		{
+			public XamlMember Member;
+			
+			public XamlMemberNode(XamlMember member)
+			{
+				this.Member = member;
+			}
+			
+			public override void WriteTo(XamlWriter writer)
+			{
+				Log("StartMember {0}", this.Member);
+				writer.WriteStartMember(this.Member);
+				Debug.Indent();
+				foreach (XamlNode node in this.Children)
+					node.WriteTo(writer);
+				Debug.Unindent();
+				Log("EndMember");
+				writer.WriteEndMember();
+			}
+		}
+		
+		sealed class XamlValueNode : XamlNode
+		{
+			public readonly object Value;
+			
+			public XamlValueNode(object value)
+			{
+				this.Value = value;
+			}
+			
+			public override void WriteTo(XamlWriter writer)
+			{
+				Log("Value {0}", this.Value);
+				Debug.Assert(this.Children.Count == 0);
+				// requires XamlReaderSettings.ValuesMustBeString = true to work properly
+				writer.WriteValue(this.Value);
+			}
+		}
+		
+		sealed class XamlNamespaceDeclarationNode : XamlNode
+		{
+			public readonly NamespaceDeclaration Namespace;
+			
+			public XamlNamespaceDeclarationNode(NamespaceDeclaration @namespace)
+			{
+				this.Namespace = @namespace;
+			}
+			
+			public override void WriteTo(XamlWriter writer)
+			{
+				Log("NamespaceDeclaration {0}", this.Namespace);
+				Debug.Assert(this.Children.Count == 0);
+				writer.WriteNamespace(this.Namespace);
+			}
+		}
+		
+		static List<XamlNode> Parse(XamlReader reader)
+		{
+			List<XamlNode> currentList = new List<XamlNode>();
+			Stack<List<XamlNode>> stack = new Stack<List<XamlNode>>();
 			while (reader.Read()) {
 				switch (reader.NodeType) {
 					case XamlNodeType.None:
-
 						break;
 					case XamlNodeType.StartObject:
-						writer.WriteStartObject(reader.Type);
+						XamlObjectNode obj = new XamlObjectNode(reader.Type);
+						currentList.Add(obj);
+						stack.Push(currentList);
+						currentList = obj.Children;
 						break;
 					case XamlNodeType.GetObject:
-						writer.WriteGetObject();
-						break;
-					case XamlNodeType.EndObject:
-						writer.WriteEndObject();
+						XamlGetObjectNode getObject = new XamlGetObjectNode();
+						currentList.Add(getObject);
+						stack.Push(currentList);
+						currentList = getObject.Children;
 						break;
 					case XamlNodeType.StartMember:
-						writer.WriteStartMember(reader.Member);
-						break;
-					case XamlNodeType.EndMember:
-						writer.WriteEndMember();
+						XamlMemberNode member = new XamlMemberNode(reader.Member);
+						currentList.Add(member);
+						stack.Push(currentList);
+						currentList = member.Children;
 						break;
 					case XamlNodeType.Value:
-						// requires XamlReaderSettings.ValuesMustBeString = true to work properly
-						writer.WriteValue(reader.Value);
+						currentList.Add(new XamlValueNode(reader.Value));
 						break;
 					case XamlNodeType.NamespaceDeclaration:
-						writer.WriteNamespace(reader.Namespace);
+						currentList.Add(new XamlNamespaceDeclarationNode(reader.Namespace));
+						break;
+					case XamlNodeType.EndObject:
+					case XamlNodeType.EndMember:
+						currentList = stack.Pop();
 						break;
 					default:
-						throw new Exception("Invalid value for XamlNodeType");
+						throw new InvalidOperationException("Invalid value for XamlNodeType");
 				}
 			}
+			if (stack.Count != 0)
+				throw new InvalidOperationException("Imbalanced stack");
+			return currentList;
+		}
+		
+		void AvoidContentProperties(XamlNode node)
+		{
+			foreach (XamlNode child in node.Children)
+				AvoidContentProperties(child);
+			
+
+			XamlObjectNode obj = node as XamlObjectNode;
+			if (obj != null) {
+				// Visit all except for the last child:
+				for (int i = 0; i < obj.Children.Count - 1; i++) {
+					// Avoids using content property syntax for simple string values, if the content property is not the last member.
+					// Without this, we cannot decompile &lt;GridViewColumn Header="Culture" DisplayMemberBinding="{Binding Culture}" /&gt;,
+					// because the Header property is the content property, but there is no way to represent the Binding as an element.
+					XamlMemberNode memberNode = obj.Children[i] as XamlMemberNode;
+					if (memberNode != null && memberNode.Member == obj.Type.ContentProperty) {
+						if (memberNode.Children.Count == 1 && memberNode.Children[0] is XamlValueNode) {
+							// By creating a clone of the XamlMember, we prevent WPF from knowing that it's the content property.
+							XamlMember member = memberNode.Member;
+							memberNode.Member = new XamlMember(member.Name, member.DeclaringType, member.IsAttachable);
+						}
+					}
+				}
+				// We also need to avoid using content properties that have a markup extension as value, as the XamlXmlWriter would always expand those:
+				for (int i = 0; i < obj.Children.Count; i++) {
+					XamlMemberNode memberNode = obj.Children[i] as XamlMemberNode;
+					if (memberNode != null && memberNode.Member == obj.Type.ContentProperty && memberNode.Children.Count == 1) {
+						XamlObjectNode me = memberNode.Children[0] as XamlObjectNode;
+						if (me != null && me.Type.IsMarkupExtension) {
+							// By creating a clone of the XamlMember, we prevent WPF from knowing that it's the content property.
+							XamlMember member = memberNode.Member;
+							memberNode.Member = new XamlMember(member.Name, member.DeclaringType, member.IsAttachable);
+						}
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// It seems like BamlReader will always output 'x:Key' as last property. However, it must be specified as attribute in valid .xaml, so we move it to the front
+		/// of the attribute list.
+		/// </summary>
+		void MoveXKeyToFront(XamlNode node)
+		{
+			foreach (XamlNode child in node.Children)
+				MoveXKeyToFront(child);
+
+			XamlObjectNode obj = node as XamlObjectNode;
+			if (obj != null && obj.Children.Count > 0) {
+				XamlMemberNode memberNode = obj.Children[obj.Children.Count - 1] as XamlMemberNode;
+				if (memberNode != null && memberNode.Member == XamlLanguage.Key) {
+					// move memberNode in front of the first member node:
+					for (int i = 0; i < obj.Children.Count; i++) {
+						if (obj.Children[i] is XamlMemberNode) {
+							obj.Children.Insert(i, memberNode);
+							obj.Children.RemoveAt(obj.Children.Count - 1);
+							break;
+						}
+					}
+				}
+			}
+		}
+		
+		public string DecompileBaml(MemoryStream bamlCode, string containingAssemblyFile)
+		{
+			bamlCode.Position = 0;
+			TextWriter w = new StringWriter();
+			
+			Assembly assembly = Assembly.LoadFile(containingAssemblyFile);
+			
+			Baml2006Reader reader = new Baml2006Reader(bamlCode, new XamlReaderSettings() { ValuesMustBeString = true, LocalAssembly = assembly });
+			var xamlDocument = Parse(reader);
+
+			foreach (var xamlNode in xamlDocument) {
+				AvoidContentProperties(xamlNode);
+				MoveXKeyToFront(xamlNode);
+			}
+			
+			XDocument doc = new XDocument();
+			XamlXmlWriter writer = new XamlXmlWriter(doc.CreateWriter(), reader.SchemaContext, new XamlXmlWriterSettings { AssumeValidInput = true });
+			foreach (var xamlNode in xamlDocument)
+				xamlNode.WriteTo(writer);
 			writer.Close();
 			
 			// Fix namespace references
@@ -78,18 +273,7 @@ namespace ICSharpCode.ILSpy.Baml
 					}
 				}
 			}
-			// Convert x:Key into an attribute where possible
-			XName xKey = XName.Get("Key", "http://schemas.microsoft.com/winfx/2006/xaml");
-			foreach (XElement e in doc.Descendants(xKey).ToList()) {
-				if (e.Nodes().Count() != 1)
-					continue;
-				XText text = e.Nodes().Single() as XText;
-				if (text != null) {
-					e.Parent.SetAttributeValue(xKey, text.Value);
-					e.Remove();
-				}
-			}
-			
+
 			return doc.ToString();
 		}