implement lazy evaluation for IEnumerable<T> and lists in debugger. Makes possible to evaluate infinite iterators and really big lists faster.

src/AddIns/Debugger/Debugger.AddIn/Tooltips/DebuggerTooltipControl.xaml

@@ -131,6 +131,7 @@
 			SelectionUnit="FullRow"
 			x:Name="dataGrid"
 			AutoGenerateColumns="False"
+			ScrollViewer.ScrollChanged="DataGrid_ScrollChanged"
 			CanUserAddRows="False"
 			HeadersVisibility="None"
 			BorderBrush="Gray"

src/AddIns/Debugger/Debugger.AddIn/Tooltips/DebuggerTooltipControl.xaml.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Windows;
 using System.Windows.Controls;
@@ -36,13 +37,16 @@ namespace Debugger.AddIn.Tooltips
 		static Point ChildPopupOffset = new Point(16, 15);
 		
 		public DebuggerTooltipControl ChildTooltip { get; private set; }
-		public IEnumerable<TreeNode> TreeNodes { get; set; }
+		readonly IEnumerator<TreeNode> treeNodesGenerator;
+		readonly ObservableCollection<TreeNode> treeNodes;
 		
-		public DebuggerTooltipControl(IEnumerable<TreeNode> treeNodes)
+		public DebuggerTooltipControl(IEnumerable<TreeNode> treeNodesGenerator)
 		{
 			InitializeComponent();
 			
-			this.TreeNodes = treeNodes;
+			this.treeNodesGenerator = treeNodesGenerator.GetEnumerator();
+			treeNodes = new ObservableCollection<TreeNode>();
+			GetNextItems();
 			this.dataGrid.ItemsSource = treeNodes;
 			
 			// Only the leaf of the tooltip has this set to false
@@ -63,7 +67,7 @@ namespace Debugger.AddIn.Tooltips
 			
 			if (clickedButton.IsChecked == true && clickedNode.GetChildren != null) {
 				Point popupPos = clickedButton.PointToScreen(ChildPopupOffset).TransformFromDevice(clickedButton);
-				this.ChildTooltip = new DebuggerTooltipControl(clickedNode.GetChildren().ToList()) {
+				this.ChildTooltip = new DebuggerTooltipControl(clickedNode.GetChildren()) {
 					// We can not use placement target otherwise we would get too deep logical tree
 					Placement = PlacementMode.Absolute,
 					HorizontalOffset = popupPos.X,
@@ -118,22 +122,23 @@ namespace Debugger.AddIn.Tooltips
 			}
 		}
 		
-		/*
-		void AnimateCloseControl(bool show)
+		void DataGrid_ScrollChanged(object sender, ScrollChangedEventArgs e)
 		{
-			DoubleAnimation animation = new DoubleAnimation();
-			animation.From = show ? 0 : 1;
-			animation.To = show ? 1 : 0;
-			animation.BeginTime = new TimeSpan(0, 0, show ? 0 : 1);
-			animation.Duration = new Duration(TimeSpan.FromMilliseconds(500));
-			animation.SetValue(Storyboard.TargetProperty, this.PinCloseControl);
-			animation.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath(Rectangle.OpacityProperty));
-			
-			Storyboard board = new Storyboard();
-			board.Children.Add(animation);
-			
-			board.Begin(this);
+			if (e.ExtentHeight > e.ViewportHeight) {
+				if (Math.Abs(e.ExtentHeight - e.VerticalOffset - e.ViewportHeight) < 2)
+					GetNextItems();
+			}
+		}
+
+		void GetNextItems(int max = 25)
+		{
+			int count = 0;
+			while (treeNodesGenerator.MoveNext()) {
+				treeNodes.Add(treeNodesGenerator.Current);
+				count++;
+				if (count >= max)
+					return;
+			}
 		}
-		*/
 	}
 }

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

@@ -24,6 +24,7 @@ using System.Linq;
 using System.Text;
 using System.Windows.Forms;
 
+using ICSharpCode.NRefactory;
 using ICSharpCode.NRefactory.CSharp;
 using ICSharpCode.NRefactory.CSharp.Refactoring;
 using Debugger.AddIn.Visualizers;
@@ -320,11 +321,7 @@ namespace Debugger.AddIn.TreeModel
 					ienumerableType.Name,
 					ienumerableType.ReflectionName,
 					string.Empty,
-					() => {
-						// Note that this will bind to the current content forever and it will not reeveluate
-						Value list = CreateListFromIEnumerable(ienumerableTypeCopy, GetValue()).GetPermanentReferenceOfHeapValue();
-						return GetIListChildren(() => list);
-					}
+					() => LazyEvaluateIEnumerableOfT(ienumerableType, GetValue())
 				);
 			}
 			
@@ -333,6 +330,59 @@ namespace Debugger.AddIn.TreeModel
 			}
 		}
 		
+		IEnumerable<TreeNode> LazyEvaluateIEnumerableOfT(ParameterizedType targetType, Value value)
+		{
+			var enumerableType = targetType.Compilation.FindType(KnownTypeCode.IEnumerableOfT).GetDefinition();
+			var enumeratorType = targetType.Compilation.FindType(KnownTypeCode.IEnumeratorOfT).GetDefinition();
+			var substitution = new TypeParameterSubstitution(targetType.TypeArguments, EmptyList<IType>.Instance);
+			IMethod getEnumerator = enumerableType.GetMethods(m => m.Name == "GetEnumerator", GetMemberOptions.IgnoreInheritedMembers)
+				.First(m => m.ReturnType.GetDefinition().Equals(enumeratorType))
+				.Specialize(substitution);
+			IMethod moveNext = enumeratorType.GetMethods(m => m.Name == "MoveNext").First();
+			IProperty current = enumeratorType.GetProperties(p => p.Name == "Current").First();
+			
+			Value enumerator;
+			GetValueException lastError;
+			enumerator = EvaluateOrError(() => Debugger.Value.InvokeMethod(WindowsDebugger.EvalThread, value, getEnumerator), out lastError);
+			if (lastError != null) {
+				yield return new TreeNode(null, "(error)", lastError.Message, string.Empty, null);
+				yield break;
+			}
+			int currentIndex = -1;
+			var moveNextResult = EvaluateOrError(() => Debugger.Value.InvokeMethod(WindowsDebugger.EvalThread, enumerator, moveNext), out lastError);
+			while (lastError == null && (bool)moveNextResult.PrimitiveValue) {
+				currentIndex++;
+				var currentValue = EvaluateOrError(() => enumerator.GetPropertyValue(WindowsDebugger.EvalThread, current), out lastError);
+				yield return new ValueNode(ClassBrowserIconService.Field, "[" + currentIndex + "]", () => currentValue);
+				moveNextResult = EvaluateOrError(() => Debugger.Value.InvokeMethod(WindowsDebugger.EvalThread, enumerator, moveNext), out lastError);
+			}
+			
+			if (lastError != null) {
+				yield return new TreeNode(null, "(error)", lastError.Message, string.Empty, null);
+				yield break;
+			}
+			
+			if (currentIndex < 0)
+				yield return new TreeNode("(empty)", null);
+		}
+		
+		Value EvaluateOrError(Func<Value> expression, out GetValueException error)
+		{
+			error = null;
+			Debugger.Value value;
+			try {
+				value = expression();
+			} catch (GetValueException ex) {
+				error = ex;
+				return null;
+			}
+			if (value.Type.GetNonInterfaceBaseTypes().Any(t => t.IsKnownType(KnownTypeCode.Exception))) {
+				error = new GetValueException(value.GetPropertyValue(WindowsDebugger.EvalThread, "Message").AsString());
+				return null;
+			}
+			return value;
+		}
+		
 		IEnumerable<TreeNode> GetMembers(IEnumerable<IMember> members)
 		{
 			foreach(var memberInfo in members.OrderBy(m => m.Name)) {

src/AddIns/Debugger/Debugger.Core/Process.cs

@@ -315,7 +315,8 @@ namespace Debugger
 		}
 		
 		/// <summary>
-		/// Indentification of the state of the debugee. This value changes whenever the state of the debugee significatntly changes
+		/// Numeric value to identify the debuggee state during a pause session.
+		/// This value changes whenever the state of the debuggee significantly changes.
 		/// </summary>
 		public long DebuggeeState {
 			get { return debuggeeState; }
@@ -337,7 +338,7 @@ namespace Debugger
 			AssertPaused();
 			pauseSession = 0;
 			if (action == DebuggeeStateAction.Clear) {
-				if (debuggeeState == 0) throw new DebuggerException("Debugee state already cleared");
+				if (debuggeeState == 0) throw new DebuggerException("Debuggee state already cleared");
 				debuggeeState = 0;
 			}
 		}
@@ -385,7 +386,7 @@ namespace Debugger
 				if (Exited != null) {
 					Exited(this, new DebuggerEventArgs() { Process = this });
 				}
-				// Expire pause seesion first
+				// Expire pause session first
 				if (IsPaused) {
 					NotifyResumed(DebuggeeStateAction.Clear);
 				}
@@ -469,7 +470,7 @@ namespace Debugger
 		}
 		
 		/// <summary>
-		/// Resume execution and run all threads not marked by the user as susspended.
+		/// Resume execution and run all threads not marked by the user as suspended.
 		/// </summary>
 		public void AsyncContinue()
 		{