Merge pull request #128 from Dirkster99/FixingMemoryLeaks

Fixing memory leaks

source/Components/AvalonDock/Controls/LayoutAnchorSideControl.cs

@@ -43,10 +43,11 @@ internal LayoutAnchorSideControl(LayoutAnchorSide model)
 		{
 			_model = model ?? throw new ArgumentNullException(nameof(model));
 			CreateChildrenViews();
-			_model.Children.CollectionChanged += (s, e) => OnModelChildrenCollectionChanged(e);
+			_model.Children.CollectionChanged += OnModelChildrenCollectionChanged;
 			UpdateSide();
-		}
 
+			Unloaded += LayoutAnchorSideControl_Unloaded;
+		}
 		#endregion Constructors
 
 		#region Properties
@@ -126,14 +127,25 @@ internal LayoutAnchorSideControl(LayoutAnchorSide model)
 		#endregion Properties
 
 		#region Private Methods
+		/// <summary>
+		/// Executes when the element is removed from within an element tree of loaded elements.
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="e"></param>
+		private void LayoutAnchorSideControl_Unloaded(object sender, RoutedEventArgs e)
+		{
+			_model.Children.CollectionChanged -= OnModelChildrenCollectionChanged;
+			Unloaded -= LayoutAnchorSideControl_Unloaded;
+		}
 
 		private void CreateChildrenViews()
 		{
 			var manager = _model.Root.Manager;
 			foreach (var childModel in _model.Children) _childViews.Add(manager.CreateUIElementForModel(childModel) as LayoutAnchorGroupControl);
 		}
 
-		private void OnModelChildrenCollectionChanged(System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+		private void OnModelChildrenCollectionChanged(object sender,
+													  System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
 		{
 			if (e.OldItems != null &&
 				(e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove ||

source/Components/AvalonDock/Controls/LayoutAnchorableControl.cs

@@ -19,18 +19,23 @@ namespace AvalonDock.Controls
 	public class LayoutAnchorableControl : Control
 	{
 		#region Constructors
-
+		/// <summary>
+		/// Static class constructor
+		/// </summary>
 		static LayoutAnchorableControl()
 		{
 			DefaultStyleKeyProperty.OverrideMetadata(typeof(LayoutAnchorableControl), new FrameworkPropertyMetadata(typeof(LayoutAnchorableControl)));
 			FocusableProperty.OverrideMetadata(typeof(LayoutAnchorableControl), new FrameworkPropertyMetadata(false));
 		}
 
+		/// <summary>
+		/// Class constructor
+		/// </summary>
 		public LayoutAnchorableControl()
 		{
 			//SetBinding(FlowDirectionProperty, new Binding("Model.Root.Manager.FlowDirection") { Source = this });
+			Unloaded += LayoutAnchorableControl_Unloaded;
 		}
-
 		#endregion Constructors
 
 		#region Properties
@@ -98,15 +103,28 @@ private void Model_PropertyChanged(object sender, System.ComponentModel.Property
 
 		#endregion Properties
 
-		#region Overrides
-
+		#region Methods
+		/// <inheritdoc/>
 		protected override void OnGotKeyboardFocus(System.Windows.Input.KeyboardFocusChangedEventArgs e)
 		{
 			if (Model != null) 
 				Model.IsActive = true;
 			base.OnGotKeyboardFocus(e);
 		}
 
-		#endregion Overrides
+		/// <summary>
+		/// Executes when the element is removed from within an element tree of loaded elements.
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="e"></param>
+		private void LayoutAnchorableControl_Unloaded(object sender, RoutedEventArgs e)
+		{
+			// prevent memory leak via event handler
+			if (Model != null)
+				Model.PropertyChanged -= Model_PropertyChanged;
+
+			Unloaded -= LayoutAnchorableControl_Unloaded;
+		}
+		#endregion Methods
 	}
 }

source/Components/AvalonDock/Controls/LayoutGridControl.cs

@@ -42,10 +42,15 @@ public abstract class LayoutGridControl<T> : Grid, ILayoutControl, IAdjustableSi
 		private Border _resizerGhost = null;
 		private Window _resizerWindowHost = null;
 		private Vector _initialStartPoint;
+		private bool _InitEvents;
 		#endregion fields
 
 		#region Constructors
-
+		/// <summary>
+		/// Class constructor
+		/// </summary>
+		/// <param name="model"></param>
+		/// <param name="orientation"></param>
 		internal LayoutGridControl(LayoutPositionableGroup<T> model, Orientation orientation)
 		{
 			_model = model ?? throw new ArgumentNullException(nameof(model));
@@ -67,24 +72,18 @@ internal LayoutGridControl(LayoutPositionableGroup<T> model, Orientation orienta
 		#endregion
 
 		#region Overrides
-
+		/// <inheritdoc/>
 		protected override void OnInitialized(EventArgs e)
 		{
 			base.OnInitialized(e);
-			_model.ChildrenTreeChanged += (s, args) =>
-				{
-					if (args.Change != ChildrenTreeChange.DirectChildrenChanged) return;
-					if (_asyncRefreshCalled.HasValue && _asyncRefreshCalled.Value == args.Change) return;
-					_asyncRefreshCalled = args.Change;
-					Dispatcher.BeginInvoke(new Action(() =>
-						{
-							_asyncRefreshCalled = null;
-							UpdateChildren();
-						}), DispatcherPriority.Normal, null);
-				};
-			this.SizeChanged += OnSizeChanged;
-		}
 
+			if (_InitEvents == false) // We'll do this only once even for multiple inits
+			{
+				_InitEvents = true;
+				_model.ChildrenTreeChanged += _model_ChildrenTreeChanged;
+				this.SizeChanged += OnSizeChanged;
+			}
+		}
 		#endregion
 
 		#region Internal Methods
@@ -100,6 +99,39 @@ protected void FixChildrenDockLengths()
 		#endregion
 
 		#region Private Methods
+		/// <summary>
+		/// Method executes when the element is removed from within an element tree of loaded elements.
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="e"></param>
+		private void OnUnloaded(object sender, RoutedEventArgs e)
+		{
+			// In order to prevent resource leaks, unsubscribe from subscribed events...
+			SizeChanged -= OnSizeChanged;
+			_model.ChildrenTreeChanged -= _model_ChildrenTreeChanged;
+
+			DetachOldSplitters();
+			DetachPropertyChangeHandler();  // Including property changed event handlers
+			Children.Clear();
+			ColumnDefinitions.Clear();
+			RowDefinitions.Clear();
+
+			Unloaded -= OnUnloaded;
+		}
+
+		private void _model_ChildrenTreeChanged(object sender, ChildrenTreeChangedEventArgs e)
+		{
+			{
+				if (e.Change != ChildrenTreeChange.DirectChildrenChanged) return;
+				if (_asyncRefreshCalled.HasValue && _asyncRefreshCalled.Value == e.Change) return;
+				_asyncRefreshCalled = e.Change;
+				Dispatcher.BeginInvoke(new Action(() =>
+				{
+					_asyncRefreshCalled = null;
+					UpdateChildren();
+				}), DispatcherPriority.Normal, null);
+			};
+		}
 
 		private void OnSizeChanged(object sender, SizeChangedEventArgs e)
 		{
@@ -114,13 +146,6 @@ private void OnSizeChanged(object sender, SizeChangedEventArgs e)
 			AdjustFixedChildrenPanelSizes();
 		}
 
-		private void OnUnloaded(object sender, RoutedEventArgs e)
-		{
-			// In order to prevent resource leaks, unsubscribe from SizeChanged events.
-			SizeChanged -= OnSizeChanged;
-			Unloaded -= OnUnloaded;
-		}
-
 		private void UpdateChildren()
 		{
 			var alreadyContainedChildren = Children.OfType<ILayoutControl>().ToArray();