Better comments.

src/AddIns/Debugger/Debugger.AddIn/TreeModel/ChildNodesOfObject.cs

@@ -98,7 +98,9 @@ namespace Debugger.AddIn.TreeModel
 		
 		public static IEnumerable<TreeNode> LazyGetItemsOfIList(Expression targetObject)
 		{
-			// This is needed for expanding IEnumerable<T>
+			// Add a cast, so that we are sure the expression has an indexer.
+			// (The expression can be e.g. of type 'object' but its value is a List.
+			// Without the cast, evaluating "expr[i]" would fail, because object does not have an indexer).
 			targetObject = new CastExpression(
 				new TypeReference(typeof(IList).FullName),
 				targetObject,
@@ -120,9 +122,9 @@ namespace Debugger.AddIn.TreeModel
 				for(int i = 0; i < count; i++) {
 					string imageName;
 					var image = ExpressionNode.GetImageForArrayIndexer(out imageName);
-					var expression = new ExpressionNode(image, "[" + i + "]", targetObject.AppendIndexer(i));
-					expression.ImageName = imageName;
-					yield return expression;
+					var itemNode = new ExpressionNode(image, "[" + i + "]", targetObject.AppendIndexer(i));
+					itemNode.ImageName = imageName;
+					yield return itemNode;
 				}
 			}
 		}

src/AddIns/Debugger/Debugger.AddIn/Visualizers/GridVisualizer/GridVisualizerWindow.xaml.cs

@@ -105,6 +105,7 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 		
 		public void Refresh()
 		{
+			try {
 				// clear ListView
 				listView.ItemsSource = null;
 				ScrollViewer listViewScroller = listView.GetScrollViewer();
@@ -124,7 +125,7 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 					// Value is IList
 					DebugType iListType, listItemType;
 					if (shownValue.Type.ResolveIListImplementation(out iListType, out listItemType)) {
-					gridValuesProvider = CreateListValuesProvider(shownExpr, iListType, listItemType);
+						gridValuesProvider = CreateListValuesProvider(shownValue, iListType, listItemType);
 					} else	{
 						// Value is IEnumerable
 						DebugType iEnumerableType, itemType;
@@ -136,7 +137,8 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 						gridValuesProvider = enumerableValuesProvider;*/
 							DebugType debugListType;
 							var debugListExpression = DebuggerHelpers.CreateDebugListExpression(shownExpr, itemType, out debugListType);
-						gridValuesProvider = CreateListValuesProvider(debugListExpression, debugListType, itemType);
+							var debugList = debugListExpression.Evaluate(WindowsDebugger.CurrentProcess);
+							gridValuesProvider = CreateListValuesProvider(debugList, debugListType, itemType);
 						} else	{
 							// Value cannot be displayed in GridVisualizer
 							return;
@@ -148,11 +150,16 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 					this.columnHider = new GridViewColumnHider((GridView)this.listView.View);
 					cmbColumns.ItemsSource = this.columnHider.HideableColumns;
 				}
+			} catch (GetValueException ex) {
+				// TODO display ex msg
+			} catch (DebuggerVisualizerException ex) {
+				// TODO display ex msg
+			}
 		}
 		
-		ListValuesProvider CreateListValuesProvider(ICSharpCode.NRefactory.Ast.Expression targetObject, DebugType iListType, DebugType listItemType)
+		ListValuesProvider CreateListValuesProvider(Value targetValue, DebugType iListType, DebugType listItemType)
 		{
-			var listValuesProvider = new ListValuesProvider(targetObject, iListType, listItemType);
+			var listValuesProvider = new ListValuesProvider(targetValue, listItemType);
 			var virtCollection = new VirtualizingCollection<ObjectValue>(listValuesProvider);
 			this.listView.ItemsSource = virtCollection;
 			return listValuesProvider;

src/AddIns/Debugger/Debugger.AddIn/Visualizers/GridVisualizer/ObjectValue.cs

@@ -16,14 +16,10 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 	/// </summary>
 	public class ObjectValue
 	{
-		private int index;
 		/// <summary> Index of this item in the collection. </summary>
-		public int Index {
-			get { return index; }
-		}
+		public int Index { get; private set; }
 		
-		// PermanentReference to one row. Even if we used expressions, they are cached using PermanentReferences, so
-		// one PermanentReference for a row would be created anyway
+		// PermanentReference for one row.
 		public Value PermanentReference { get; private set; }
 		
 		private Dictionary<string, ObjectProperty> properties = new Dictionary<string, ObjectProperty>();
@@ -33,7 +29,7 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 		
 		internal ObjectValue(int index, Dictionary<string, MemberInfo> memberFromNameMap)
 		{
-			this.index = index;
+			this.Index = index;
 			this.memberForNameMap = memberFromNameMap;
 		}
 
@@ -60,7 +56,6 @@ namespace Debugger.AddIn.Visualizers.GridVisualizer
 				}
 				return property;
 			}
-			//set	{ properties[key] = value; }
 		}
 		
 		public static ObjectValue Create(Debugger.Value value, int index, Dictionary<string, MemberInfo> memberFromName)