- lazy evaluation of node content

- better displaying of exceptions

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@4377 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Common/ObjectPropertyComparer.cs

@@ -14,6 +14,12 @@ namespace Debugger.AddIn.Visualizers.Common
 	/// </summary>
 	class ObjectPropertyComparer : IComparer<ObjectProperty>
 	{
+		private static readonly ObjectPropertyComparer instance = new ObjectPropertyComparer();
+		public static ObjectPropertyComparer Instance
+		{
+			get { return instance; }
+		}
+		
 		public int Compare(ObjectProperty prop1, ObjectProperty prop2)
 		{
 			// order by IsAtomic, Name

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Drawing/GraphDrawer.cs

@@ -89,7 +89,6 @@ namespace Debugger.AddIn.Visualizers.Graph
 					anim.Completed += new EventHandler((o, e) => { Draw(newGraph); });
 					first = false;
 				}
-				//anim.From = new Point(Canvas.GetLeft(node.NodeVisualControl), Canvas.GetTop(node.NodeVisualControl));
 				anim.From = node.LeftTop;
 				
 				anim.To = newNode.LeftTop;
@@ -122,7 +121,7 @@ namespace Debugger.AddIn.Visualizers.Graph
 			}
 		}
 		
-		private NodeControl addNodeToCanvas(PositionedGraphNode node)
+		private PositionedGraphNodeControl addNodeToCanvas(PositionedGraphNode node)
 		{
 			canvas.Children.Add(node.NodeVisualControl);
 			Canvas.SetLeft(node.NodeVisualControl, node.Left);

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Drawing/NodeControl.xaml.cs

@@ -72,7 +72,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 			{
 				Button btnExpandCollapse = new Button();
 				btnExpandCollapse.Tag = property;
-				btnExpandCollapse.Content = property.IsExpanded ? "-" : "+";
+				btnExpandCollapse.Content = property.IsPropertyExpanded ? "-" : "+";
 				btnExpandCollapse.Width = 20;
 				propertyGrid.Children.Add(btnExpandCollapse);
 				Grid.SetRow(btnExpandCollapse, nRow);
@@ -110,9 +110,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 			Button buttonClicked = ((Button)sender);
 			var property = (PositionedNodeProperty)buttonClicked.Tag;
 			
-			property.IsExpanded = !property.IsExpanded;
-			buttonClicked.Content = property.IsExpanded ? "-" : "+";
-			if (property.IsExpanded)
+			property.IsPropertyExpanded = !property.IsPropertyExpanded;
+			buttonClicked.Content = property.IsPropertyExpanded ? "-" : "+";
+			if (property.IsPropertyExpanded)
 			{
 				OnPropertyExpanded(property);
 			}

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Drawing/PositionedGraphNodeControl.xaml

@@ -48,12 +48,12 @@
                         </GridView.ColumnHeaderContainerStyle>
                         <GridView.Columns>
                         	   <!-- Expand button (either property or nested) -->
-                            <GridViewColumn Header="Plus" Width="Auto">
+                            <GridViewColumn Header="Plus" Width="35">
                                 <GridViewColumn.CellTemplate>
                                     <DataTemplate>
                                         <StackPanel>
-                                            <ToggleButton x:Name="Expander" Width="20" IsChecked="{Binding IsExpanded}" Click="NestedExpandButton_Click" Padding="0" Margin="0 0 6 0">+</ToggleButton>
-                                            <ToggleButton x:Name="PropertyExpander" Click="PropertyExpandButton_Click" Padding="0" Margin="0 0 6 0">+p</ToggleButton>
+                                            <ToggleButton x:Name="Expander" Width="20" Margin="0" IsChecked="{Binding IsExpanded}" Click="NestedExpandButton_Click" Padding="0">+</ToggleButton>
+                                            <ToggleButton x:Name="PropertyExpander" Width="20" Margin="0" IsChecked="{Binding IsPropertyExpanded}" Click="PropertyExpandButton_Click" Padding="0">+</ToggleButton>
                                         </StackPanel>
                                         <DataTemplate.Triggers>
                                             <DataTrigger Binding="{Binding Path=HasChildren}" Value="False">
@@ -65,24 +65,29 @@
                                                     Property="Visibility" Value="Collapsed"/>
                                             </DataTrigger>
                                         </DataTemplate.Triggers>
+											
                                     </DataTemplate>
                                 </GridViewColumn.CellTemplate>
                             </GridViewColumn>
                         	   <!-- Name -->
-                            <GridViewColumn Header="Name" Width="Auto">
+                            <GridViewColumn Header="Name" Width="80">
                                 <GridViewColumn.CellTemplate>
                                     <DataTemplate>
-                                        <StackPanel Orientation="Horizontal">
-                                            <TextBlock Text="{Binding Name}" MinWidth="100"></TextBlock>
-                                        </StackPanel>
+                                        		<!--
+                                        		<TextBlock Text="hello" MinWidth="100"></TextBlock>
+												-->
+                                            <TextBlock Text="{Binding Name}" MinWidth="80"></TextBlock>
                                     </DataTemplate>
                                 </GridViewColumn.CellTemplate>
                             </GridViewColumn>
                         	   <!-- Text -->
-                            <GridViewColumn Header="Value" Width="Auto">
+                            <GridViewColumn Header="Value" Width="80">
                                 <GridViewColumn.CellTemplate>
                                     <DataTemplate>
-                                        <TextBlock Text="{Binding Text}" MinWidth="100"></TextBlock>
+                                    		<!--
+                                    		<TextBlock Text="val" MinWidth="100"></TextBlock>
+											-->
+                                        <TextBlock Text="{Binding Text}" MinWidth="80"></TextBlock>
                                     </DataTemplate>
                                 </GridViewColumn.CellTemplate>
                             </GridViewColumn>

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Drawing/PositionedGraphNodeControl.xaml.cs

@@ -52,7 +52,6 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 				this.view = initializeView(this.root);
 				// data virtualization, PropertyNodeViewModel implements IEvaluate
 				this.listView.ItemsSource = new VirtualizingObservableCollection<NestedNodeViewModel>(this.view);
-				//listView.AddHandler(ScrollViewer.ScrollChangedEvent, new ScrollChangedEventHandler(listView_ScrollChanged));
 			}
 		}
 		
@@ -75,9 +74,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 			}
 			
 			PositionedNodeProperty property = clickedNode.Property;
-			property.IsExpanded = !property.IsExpanded;
-			clickedButton.Content = property.IsExpanded ? "-p" : "+p";
-			if (property.IsExpanded)
+			//property.IsPropertyExpanded = !property.IsPropertyExpanded;  // done by databinding
+			clickedButton.Content = property.IsPropertyExpanded ? "-" : "+";
+			if (property.IsPropertyExpanded)
 			{
 				OnPropertyExpanded(property);
 			}
@@ -115,8 +114,6 @@ namespace Debugger.AddIn.Visualizers.Graph.Drawing
 				}
 			}
 
-			var a = new ListViewItem();
-
 			// set to Auto again to resize columns
 			var colName = (this.listView.View as GridView).Columns[0];
 			var colValue = (this.listView.View as GridView).Columns[1];

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/NestedNodeViewModel.cs

@@ -21,20 +21,19 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			
 			this.containingNode = containingNode;
 		}
-
 		
 		/// <summary>
 		/// Name displayed in GUI.
 		/// </summary>
-		public string Name { get; protected set; }
+		public string Name { get; set; }
 		/// <summary>
 		/// Text displayed in GUI.
 		/// </summary>
-		public string Text { get; protected set; }
+		public string Text { get; set; }
 		/// <summary>
 		/// Is this expandable node?
 		/// </summary>
-		public bool IsNested { get; protected set; }
+		public bool IsNested { get; set; }
 		/// <summary>
 		/// Does this node have any children?
 		/// </summary>

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/PositionedGraphNode.cs

@@ -25,6 +25,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			this.objectNode = objectNode;
 		}
 		
+		public event EventHandler<PositionedPropertyEventArgs> PropertyExpanded;
+		public event EventHandler<PositionedPropertyEventArgs> PropertyCollapsed;
+		
 		private ObjectGraphNode objectNode;
 		/// <summary>
 		/// Underlying ObjectNode.
@@ -34,8 +37,25 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			get { return objectNode; }
 		}
 		
-		public event EventHandler<PositionedPropertyEventArgs> PropertyExpanded;
-		public event EventHandler<PositionedPropertyEventArgs> PropertyCollapsed;
+		/// <summary>
+		/// Tree-of-properties content of this node.
+		/// </summary>
+		public NestedNodeViewModel Content 
+		{ 
+			get; set;
+		}
+		
+		private PositionedGraphNodeControl nodeVisualControl;
+		/// <summary>
+		/// Visual control to be shown for this node.
+		/// </summary>
+		public PositionedGraphNodeControl NodeVisualControl
+		{
+			get
+			{
+				return this.nodeVisualControl;
+			}
+		}
 		
 		// TODO posNodeForObjectGraphNode will be a service, that will return existing posNodes or create empty new
 		public void InitContentFromObjectNode()
@@ -46,7 +66,8 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		
 		public void InitView()
 		{
-			this.nodeVisualControl = new NodeControl();
+			this.nodeVisualControl = new PositionedGraphNodeControl();
+			this.nodeVisualControl.MaxHeight = 200;
 			
 			this.nodeVisualControl.PropertyExpanded += new EventHandler<PositionedPropertyEventArgs>(NodeVisualControl_Expanded);
 			this.nodeVisualControl.PropertyCollapsed += new EventHandler<PositionedPropertyEventArgs>(NodeVisualControl_Collapsed);
@@ -54,20 +75,12 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		
 		public void FillView()
 		{
-			//this.nodeVisualControl.Root = this.Content;
-			foreach (var property in this.Properties)
+			this.nodeVisualControl.Root = this.Content;
+			/*foreach (var property in this.Properties)
 			{
 				property.Evaluate();
 				this.nodeVisualControl.AddProperty(property);
-			}
-		}
-		
-		/// <summary>
-		/// Tree-of-properties content of this node.
-		/// </summary>
-		public NestedNodeViewModel Content 
-		{ 
-			get; set;
+			}*/
 		}
 		
 		// TODO do proper tree iteration
@@ -83,17 +96,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			}
 		}
 		
-		private NodeControl nodeVisualControl;
-		/// <summary>
-		/// Visual control to be shown for this node.
-		/// </summary>
-		public NodeControl NodeVisualControl
-		{
-			get
-			{
-				return this.nodeVisualControl;
-			}
-		}
+		
 		
 		public virtual IEnumerable<PositionedEdge> Edges
 		{

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/PositionedNodeProperty.cs

@@ -32,7 +32,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		/// <summary>
 		/// Is this property expanded?
 		/// </summary>
-		public bool IsExpanded { get; set; }
+		public bool IsPropertyExpanded { get; set; }
 		
 		/// <summary>
 		/// Edge outgoing from this property to another <see cref="PositionedNode"/>.

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/PropertyNodeViewModel.cs

@@ -32,6 +32,12 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			get { return this.positionedProperty.IsEvaluated; }
 		}
 		
+		public bool IsPropertyExpanded
+		{
+			get { return this.positionedProperty.IsPropertyExpanded; }
+			set { this.positionedProperty.IsPropertyExpanded = value; }
+		}
+		
 		public void Evaluate()
 		{
 			this.positionedProperty.Evaluate();
@@ -46,10 +52,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			PropertyNode sourcePropertyNode = source as PropertyNode;
 			
 			this.Name = sourcePropertyNode.Property.Name;
-			this.Text = "";		// lazy evaluated
+			this.Text = sourcePropertyNode.Property.Value;		// lazy evaluated
 			this.IsNested = false;
 			this.IsExpanded = false;
-			this.Name = sourcePropertyNode.Property.Name;
 			this.positionedProperty = new PositionedNodeProperty(sourcePropertyNode.Property, this.ContainingNode);
 		}
 	}

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/Tree/LayoutDirection.cs

@@ -13,9 +13,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 	/// </summary>
 	public enum LayoutDirection
 	{
-		[Display("Top to bottom")]
-		TopBottom,
 		[Display("Left to right")]
-		LeftRight
+		LeftRight,
+		[Display("Top to bottom")]
+		TopBottom
 	}
 }

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/Layout/Tree/TreeLayouter.cs

@@ -22,8 +22,6 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		
 		private LayoutDirection layoutDirection = LayoutDirection.TopBottom;
 		
-		PositionedGraph resultGraph = null;
-		
 		HashSet<PositionedGraphNode> seenNodes = new HashSet<PositionedGraphNode>();
 		Dictionary<ObjectGraphNode, PositionedGraphNode> treeNodeFor = new Dictionary<ObjectGraphNode, PositionedGraphNode>();
 		
@@ -46,11 +44,11 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			//TreeGraphNode tree = buildTreeRecursive(objectGraph.Root, expandedNodes);
 			
 			// convert ObjectGraph to PositionedGraph with TreeEdges
-			PositionedGraph tree = buildTreeGraph(objectGraph, expandedNodes);
-			// first pass
-			calculateSubtreeSizes((TreeGraphNode)tree.Root);
-			// second pass
-			calculateNodePosRecursive((TreeGraphNode)tree.Root, 0, 0);
+			var resultGraph = buildTreeGraph(objectGraph, expandedNodes);
+			// first layout pass
+			calculateSubtreeSizes((TreeGraphNode)resultGraph.Root);
+			// second layout pass
+			calculateNodePosRecursive((TreeGraphNode)resultGraph.Root, 0, 0);
 			
 			var neatoRouter = new NeatoEdgeRouter();
 			resultGraph = neatoRouter.CalculateEdges(resultGraph);
@@ -60,10 +58,10 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		
 		private PositionedGraph buildTreeGraph(ObjectGraph objectGraph, ExpandedNodes expandedNodes)
 		{
-			resultGraph = new PositionedGraph();
+			var resultGraph = new PositionedGraph();
 			
 			// create empty PosNodes
-			foreach (ObjectGraphNode objectGraphNode in objectGraph.Nodes)
+			foreach (ObjectGraphNode objectGraphNode in objectGraph.ReachableNodes)
 			{
 				TreeGraphNode posNode = createNewTreeGraphNode(objectGraphNode); 
 				resultGraph.AddNode(posNode);
@@ -84,7 +82,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 				// create edges outgoing from this posNode
 				foreach (PositionedNodeProperty property in posNode.Properties)
 				{
-					property.IsExpanded = expandedNodes.IsExpanded(property.Expression.Code);
+					property.IsPropertyExpanded = expandedNodes.IsExpanded(property.Expression.Code);
 					
 					if (property.ObjectGraphProperty.TargetNode != null)
 					{
@@ -137,54 +135,6 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 			return newGraphNode;
 		}
 		
-		/*private TreeGraphNode buildTreeRecursive(ObjectGraphNode objectGraphNode, ExpandedNodes expandedNodes)
-		{
-			seenNodes.Add(objectGraphNode, null);
-			
-			TreeGraphNode newTreeNode = createNewTreeGraphNode(); 
-			resultGraph.AddNode(newTreeNode);
-			treeNodeFor[objectGraphNode] = newTreeNode;
-			
-			double subtreeSize = 0;
-			foreach	(AbstractNode absNode in objectGraphNode.Content.Children)
-			{
-				var newTreeNodeContent = new NestedNodeViewModel();
-				
-				
-				ObjectGraphProperty property = ((PropertyNode)absNode).Property;
-				
-				if (property.TargetNode != null)
-				{
-					ObjectGraphNode neighbor = property.TargetNode;
-					TreeGraphNode targetTreeNode = null;
-					bool newEdgeIsTreeEdge = false;
-					if (seenNodes.ContainsKey(neighbor))
-					{
-						targetTreeNode = treeNodeFor[neighbor];
-						newEdgeIsTreeEdge = false;
-					}
-					else
-					{
-						targetTreeNode = buildTreeRecursive(neighbor, expandedNodes);
-						newEdgeIsTreeEdge = true;
-						subtreeSize += targetTreeNode.SubtreeSize;
-					}
-					var posNodeProperty = newTreeNode.AddProperty(property, expandedNodes.IsExpanded(property.Expression.Code));
-					posNodeProperty.Edge = new TreeGraphEdge { IsTreeEdge = newEdgeIsTreeEdge, Name = property.Name, Source = posNodeProperty, Target = targetTreeNode };
-				}
-				else
-				{
-					// property.Edge stays null
-					newTreeNode.AddProperty(property, expandedNodes.IsExpanded(property.Expression.Code));
-				}
-			}
-			
-			newTreeNode.Measure();
-			newTreeNode.SubtreeSize = Math.Max(newTreeNode.LateralSizeWithMargin, subtreeSize);
-			
-			return newTreeNode;
-		}*/
-		
 		/// <summary>
 		/// Given SubtreeSize for each node, positions the nodes, in a left-to-right or top-to-bottom fashion.
 		/// </summary>

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/ObjectGraph/ObjectGraph.cs

@@ -38,22 +38,28 @@ namespace Debugger.AddIn.Visualizers.Graph
             get { return _nodes; }
         }
        
-        /*
-        /// <summary>
-        /// All edges in the graph.
-        /// </summary>
-        public IEnumerable<ObjectEdge> Edges
+        // HACK to support expanding/collapsing, because expanding is done by modifying ObjectGraph and rebuiling PosGraph
+        public IEnumerable<ObjectGraphNode> ReachableNodes 
+        {
+        	get 
+        	{
+        		var seenNodes = new HashSet<ObjectGraphNode>();
+        		determineReachableNodes(this.Root, seenNodes);
+        		foreach	(var node in seenNodes)
+        		{
+        			yield return node;
+        		}
+        	}
+        }
+        private void determineReachableNodes(ObjectGraphNode root, HashSet<ObjectGraphNode> seenNodes)
         {
-            get 
-            {
-            	foreach	(ObjectNode node in this.Nodes)
-            	{
-            		foreach (ObjectEdge edge in node.Edges)
-            		{
-            			yield return edge;
-            		}
-            	}
+        	seenNodes.Add(root);
+        	
+        	foreach(var prop in root.ComplexProperties)
+        	{
+        		if (prop.TargetNode != null && !seenNodes.Contains(prop.TargetNode))
+        			determineReachableNodes(prop.TargetNode, seenNodes);
         	}
-        }*/
+        }
     }
 }

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/ObjectGraph/ObjectGraphBuilder.cs

@@ -11,6 +11,7 @@ using Debugger;
 using Debugger.MetaData;
 using Debugger.Expressions;
 using Debugger.AddIn.Visualizers.Utils;
+using Debugger.AddIn.Visualizers.Common;
 
 namespace Debugger.AddIn.Visualizers.Graph
 {
@@ -79,13 +80,18 @@ namespace Debugger.AddIn.Visualizers.Graph
 		{
 			if (string.IsNullOrEmpty(expression))
 			{
-				throw new DebuggerVisualizerException("Expression cannot be empty.");
+				throw new DebuggerVisualizerException("Expression is empty.");
 			}
 			
 			resultGraph = new ObjectGraph();
+			Value rootValue = debuggerService.GetValueFromName(expression);
+			if (rootValue == null)
+			{
+				throw new DebuggerVisualizerException("Please use the visualizer when debugging.");
+			}
 			
 			// empty graph for null expression
-			if (!debuggerService.GetValueFromName(expression).IsNull)
+			if (!rootValue.IsNull)
 			{
 				//resultGraph.Root = buildGraphRecursive(debuggerService.GetValueFromName(expression).GetPermanentReference(), expandedNodes);
 				resultGraph.Root = createNewNode(debuggerService.GetValueFromName(expression).GetPermanentReference());
@@ -135,8 +141,20 @@ namespace Debugger.AddIn.Visualizers.Graph
 			NestedNode contentRoot = new NestedNode(NestedNodeType.ThisNode);
 			thisNode.Content = contentRoot;
 			
+			var propertyList = getProperties(thisNode.PermanentReference);
+			propertyList.Sort(ObjectPropertyComparer.Instance);
+			foreach (var property in propertyList)
+			{
+				contentRoot.AddChild(new PropertyNode(property));
+			}
+		}
+		
+		private List<ObjectGraphProperty> getProperties(Value value)
+		{
+			List<ObjectGraphProperty> propertyList = new List<ObjectGraphProperty>();
+			
 			// take all properties for this value (type = value's real type)
-			foreach(Expression memberExpr in thisNode.PermanentReference.Expression.AppendObjectMembers(thisNode.PermanentReference.Type, this.memberBindingFlags))
+			foreach(Expression memberExpr in value.Expression.AppendObjectMembers(value.Type, this.memberBindingFlags))
 			{
 				checkIsOfSupportedType(memberExpr);
 				
@@ -145,15 +163,17 @@ namespace Debugger.AddIn.Visualizers.Graph
 				{
 					// properties are now lazy-evaluated
 					//  string memberValueAsString = memberExpr.Evaluate(debuggerService.DebuggedProcess).InvokeToString();
-					AddAtomicPropertyChild(contentRoot, memberName, memberExpr);
+					propertyList.Add(createAtomicProperty(memberName, memberExpr));
 				}
 				else
 				{
 					ObjectGraphNode targetNode = null;
 					bool memberIsNull = memberExpr.IsNull();
-					AddComplexPropertyChild(contentRoot, memberName, memberExpr, targetNode, memberIsNull);
+					propertyList.Add(createComplesProperty(memberName, memberExpr, targetNode, memberIsNull));
 				}
 			}
+			
+			return propertyList;
 		}
 		
 		/// <summary>
@@ -238,24 +258,18 @@ namespace Debugger.AddIn.Visualizers.Graph
 			}
 		}
 		
-		/// <summary>
-		/// Adds primitive property.
-		/// </summary>
-		public void AddAtomicPropertyChild(NestedNode node, string name, Expression expression)
+		public ObjectGraphProperty createAtomicProperty(string name, Expression expression)
 		{
-			// add child with no value (will be lazy-evaluated later)
-			node.AddChild(new PropertyNode(new ObjectGraphProperty
-			                               { Name = name, Value = "", Expression = expression, IsAtomic = true, TargetNode = null }));
+			// value is empty (will be lazy-evaluated later)
+			return new ObjectGraphProperty
+			         { Name = name, Value = "", Expression = expression, IsAtomic = true, TargetNode = null };
 		}
 		
-		/// <summary>
-		/// Adds complex property.
-		/// </summary>
-		public void AddComplexPropertyChild(NestedNode node, string name, Expression expression, ObjectGraphNode targetNode, bool isNull)
+		public ObjectGraphProperty createComplesProperty(string name, Expression expression, ObjectGraphNode targetNode, bool isNull)
 		{
-			// add child with no value (will be lazy-evaluated later)
-			node.AddChild(new PropertyNode(new ObjectGraphProperty
-			                               { Name = name, Value = "", Expression = expression, IsAtomic = false, TargetNode = targetNode, IsNull = isNull }));
+			// value is empty (will be lazy-evaluated later)
+			return new ObjectGraphProperty
+			         { Name = name, Value = "", Expression = expression, IsAtomic = false, TargetNode = targetNode, IsNull = isNull };
 		}
 		
 		/// <summary>

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/VisualizerWPFWindow.xaml

@@ -22,17 +22,24 @@
             </StackPanel.Resources>
 
             <Border Margin="3" Padding="3">
+            	<StackPanel Orientation="Vertical">
                 <StackPanel Orientation="Horizontal">
                     <TextBlock VerticalAlignment="Center">Expression:</TextBlock>
                     <TextBox Name="txtExpression" VerticalAlignment="Center" Width="100"></TextBox>
                     <Button Click="Inspect_Button_Click">Inspect</Button>
+            		  <TextBlock Margin="12 0 6 0" VerticalAlignment="Center">Layout:</TextBlock>
+                    <ComboBox Name="cmbLayoutDirection" Width="150" ItemsSource="{Binding Path=EnumValues}" SelectedValue="{Binding Path=SelectedEnumValue}" SelectedValuePath="EnumValue" DisplayMemberPath="DisplayValue"></ComboBox>
+                </StackPanel>
+        		 <StackPanel Orientation="Horizontal" Name="pnlError" Visibility="Collapsed" Margin="0 6 0 0">
+                    <TextBlock Margin="0 0 4 0" Name="lblError" FontStyle="Italic">Error: </TextBlock>
+                    <TextBlock Margin="0 0 0 0" Name="txtError" FontStyle="Italic"></TextBlock>
                 </StackPanel>
+				</StackPanel>
             </Border>
             
             <Border Margin="3" Padding="3">
                 <StackPanel Orientation="Horizontal">
-                    <TextBlock VerticalAlignment="Center">Layout:</TextBlock>
-                    <ComboBox Name="cmbLayoutDirection" Width="150" ItemsSource="{Binding Path=EnumValues}" SelectedValue="{Binding Path=SelectedEnumValue}" SelectedValuePath="EnumValue" DisplayMemberPath="DisplayValue"></ComboBox>
+                    
                 </StackPanel>
             </Border>
         </StackPanel>

src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Visualizers/Graph/VisualizerWPFWindow.xaml.cs

@@ -92,49 +92,62 @@ namespace Debugger.AddIn.Visualizers.Graph
 		
 		void refreshGraph()
 		{
-			this.objectGraph = rebuildGraph();
-			layoutGraph(this.objectGraph);
-			//GraphDrawer drawer = new GraphDrawer(graph);
-			//drawer.Draw(canvas);
-		}
-		
-		ObjectGraph rebuildGraph()
-		{
-			this.objectGraphBuilder = new ObjectGraphBuilder(debuggerService);
+			bool graphBuiltOk = true;
+			guiClearException();
 			try
 			{
-				ICSharpCode.Core.LoggingService.Debug("Debugger visualizer: Building graph for expression: " + txtExpression.Text);
-				return this.objectGraphBuilder.BuildGraphForExpression(txtExpression.Text, this.expandedNodes);
+				this.objectGraph = rebuildGraph();
 			}
 			catch(DebuggerVisualizerException ex)
 			{
+				graphBuiltOk = false;
 				guiHandleException(ex);
-				return null;
 			}
 			catch(Debugger.GetValueException ex)
 			{
+				graphBuiltOk = false;
 				guiHandleException(ex);
-				return null;
+			}
+			if (graphBuiltOk)
+			{
+				layoutGraph(this.objectGraph);
 			}
 		}
 		
+		ObjectGraph rebuildGraph()
+		{
+			this.objectGraphBuilder = new ObjectGraphBuilder(debuggerService);
+			ICSharpCode.Core.LoggingService.Debug("Debugger visualizer: Building graph for expression: " + txtExpression.Text);
+			return this.objectGraphBuilder.BuildGraphForExpression(txtExpression.Text, this.expandedNodes);
+		}
+		
 		void layoutGraph(ObjectGraph graph)
 		{
-			ICSharpCode.Core.LoggingService.Debug("Debugger visualizer: Calculating graph layout");
 			Layout.TreeLayouter layouter = new Layout.TreeLayouter();
-			
+
 			this.oldPosGraph = this.currentPosGraph;
+			
+			ICSharpCode.Core.LoggingService.Debug("Debugger visualizer: Calculating graph layout");
 			this.currentPosGraph = layouter.CalculateLayout(graph, layoutViewModel.SelectedEnumValue, this.expandedNodes);
+			ICSharpCode.Core.LoggingService.Debug("Debugger visualizer: Graph layout completed");
+			
 			registerExpandCollapseEvents(this.currentPosGraph);
 			
-			//var graphDiff = new GraphMatcher().MatchGraphs(oldPosGraph, currentPosGraph);
-			//this.graphDrawer.StartAnimation(oldPosGraph, currentPosGraph, graphDiff);
-			this.graphDrawer.Draw(this.currentPosGraph);
+			var graphDiff = new GraphMatcher().MatchGraphs(oldPosGraph, currentPosGraph);
+			this.graphDrawer.StartAnimation(oldPosGraph, currentPosGraph, graphDiff);
+			//this.graphDrawer.Draw(this.currentPosGraph);
+		}
+		
+		void guiClearException()
+		{
+			this.pnlError.Visibility = Visibility.Collapsed;
 		}
 		
 		void guiHandleException(System.Exception ex)
 		{
-			MessageBox.Show(ex.Message, "Exception", MessageBoxButton.OK, MessageBoxImage.Error);
+			this.txtError.Text = ex.Message;
+			this.pnlError.Visibility = Visibility.Visible;
+			//MessageBox.Show(ex.Message, "Exception", MessageBoxButton.OK, MessageBoxImage.Error);
 		}
 		
 		void registerExpandCollapseEvents(PositionedGraph posGraph)