Expand foldings when the caret is moved into them.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@4856 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/ParserFoldingStrategy.cs

@@ -31,6 +31,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		{
 			this.textArea = textArea;
 			foldingManager = new FoldingManager(textArea.TextView, textArea.Document);
+			foldingManager.ExpandFoldingsWhenCaretIsMovedIntoThem(textArea.Caret);
 			margin = new FoldingMargin() { FoldingManager = foldingManager, TextView = textArea.TextView };
 			generator = new FoldingElementGenerator() { FoldingManager = foldingManager };
 			textArea.LeftMargins.Add(margin);

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Editing/Caret.cs

@@ -221,6 +221,7 @@ namespace ICSharpCode.AvalonEdit.Editing
 		/// This event might be raised multiple times during a big update operation.
 		/// You might want to check TextDocument.IsInUpdate and delay time-consuming
 		/// actions until the update operation ends.
+		/// TODO: only raise this event outside of document updates
 		/// </summary>
 		public event EventHandler PositionChanged;
 		

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Editing/CaretWeakEventHandler.cs

@@ -0,0 +1,37 @@
+/*
+ * Created by SharpDevelop.
+ * User: daniel
+ * Date: 31.08.2009
+ * Time: 21:06
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+using ICSharpCode.AvalonEdit.Utils;
+using System;
+
+namespace ICSharpCode.AvalonEdit.Editing
+{
+	/// <summary>
+	/// Contains classes for handling weak events on the Caret class.
+	/// </summary>
+	public static class CaretWeakEventManager
+	{
+		/// <summary>
+		/// Handles the Caret.PositionChanged event.
+		/// </summary>
+		public sealed class PositionChanged : WeakEventManagerBase<PositionChanged, Caret>
+		{
+			/// <inheritdoc/>
+			protected override void StartListening(Caret source)
+			{
+				source.PositionChanged += DeliverEvent;
+			}
+			
+			/// <inheritdoc/>
+			protected override void StopListening(Caret source)
+			{
+				source.PositionChanged -= DeliverEvent;
+			}
+		}
+	}
+}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Editing/FoldingManager.cs

@@ -8,10 +8,11 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Windows;
+using System.Windows.Threading;
 
 using ICSharpCode.AvalonEdit.Document;
 using ICSharpCode.AvalonEdit.Rendering;
-using System.Windows.Threading;
 
 namespace ICSharpCode.AvalonEdit.Editing
 {
@@ -39,6 +40,45 @@ namespace ICSharpCode.AvalonEdit.Editing
 			this.foldings = new TextSegmentCollection<FoldingSection>(document);
 		}
 		
+		// keep a reference to the helper as long as the folding manager exists
+		ExpandFoldingsWhenCaretIsMovedIntoThemHelper helper;
+		
+		/// <summary>
+		/// Will listen to Caret.PositionChanged events and automatically expand folding sections
+		/// when the caret is moved into them.
+		/// </summary>
+		public void ExpandFoldingsWhenCaretIsMovedIntoThem(Caret caret)
+		{
+			if (helper == null)
+				helper = new ExpandFoldingsWhenCaretIsMovedIntoThemHelper(this);
+			CaretWeakEventManager.PositionChanged.AddListener(caret, helper);
+		}
+		
+		sealed class ExpandFoldingsWhenCaretIsMovedIntoThemHelper : IWeakEventListener
+		{
+			FoldingManager manager;
+			
+			public ExpandFoldingsWhenCaretIsMovedIntoThemHelper(FoldingManager manager)
+			{
+				this.manager = manager;
+			}
+			
+			bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
+			{
+				if (managerType == typeof(CaretWeakEventManager.PositionChanged)) {
+					Caret caret = (Caret)sender;
+					int caretOffset = caret.Offset;
+					foreach (FoldingSection s in manager.GetFoldingsContaining(caretOffset)) {
+						if (s.IsFolded && s.StartOffset < caretOffset && caretOffset < s.EndOffset) {
+							s.IsFolded = false;
+						}
+					}
+					return true;
+				}
+				return false;
+			}
+		}
+		
 		/// <summary>
 		/// Creates a folding for the specified text section.
 		/// </summary>

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/ICSharpCode.AvalonEdit.csproj

@@ -131,6 +131,7 @@
     </Compile>
     <Compile Include="Editing\CaretNavigationCommandHandler.cs">
     </Compile>
+    <Compile Include="Editing\CaretWeakEventHandler.cs" />
     <Compile Include="Editing\DragDropException.cs" />
     <Compile Include="Editing\EditingCommandHandler.cs" />
     <Compile Include="Editing\FoldingElementGenerator.cs">