Merge pull request #219 from miroiu/fix/218-memory-leak

Fix memory leak caused by auto panning timer

Author: miroiu

CHANGELOG.md

@@ -7,7 +7,8 @@
 >	- Added AsRef extension method to InputGesture to convert it to an InputGestureRef
 > - Bugfixes:
 >	- Fixed an issue where the gesture used for EditorGestures.Editor.SelectAll extracted from the ApplicationCommands was assumed to be a KeyGesture
->	- Fixed overrides of DrawDefaultArrowhead and DrawDirectionalArrowheadGeometry virtual methods not working in subclasses of the built in connections
+>	- Fixed overrides of DrawDirectionalArrowheadGeometry virtual method not working in subclasses of the built in connections
+>	- Fixed a memory leak caused by the auto panning timer
 
 #### **Version 7.0.3**
 

Examples/Nodify.Calculator/EditorView.xaml.cs

@@ -1,42 +1,57 @@
-using System.Windows;
+using Nodify.Interactivity;
+using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 
 namespace Nodify.Calculator
 {
-    public partial class EditorView : UserControl
+    public class OperationsMenuHandler : InputElementState<NodifyEditor>
     {
-        public EditorView()
-        {
-            InitializeComponent();
+        private static InputGesture OpenGesture { get; } = new Interactivity.MouseGesture(MouseAction.RightClick);
+        private static InputGesture CloseGesture { get; } = new Interactivity.MouseGesture(MouseAction.LeftClick);
+
+        private OperationsMenuViewModel ViewModel => ((CalculatorViewModel)Element.DataContext).OperationsMenu;
 
-            EventManager.RegisterClassHandler(typeof(NodifyEditor), MouseLeftButtonDownEvent, new MouseButtonEventHandler(CloseOperationsMenu), true);
-            EventManager.RegisterClassHandler(typeof(NodifyEditor), MouseRightButtonUpEvent, new MouseButtonEventHandler(OpenOperationsMenu));
+        public OperationsMenuHandler(NodifyEditor element) : base(element)
+        {
         }
 
-        private void OpenOperationsMenu(object sender, MouseButtonEventArgs e)
+        protected override void OnMouseUp(MouseButtonEventArgs e)
         {
-            if (e.OriginalSource is NodifyEditor editor && editor.DataContext is CalculatorViewModel calculator)
+            if (OpenGesture.Matches(e.Source, e))
             {
-                e.Handled = true;
-                calculator.OperationsMenu.OpenAt(editor.MouseLocation);
+                ViewModel.OpenAt(Element.MouseLocation);
             }
         }
 
-        private void CloseOperationsMenu(object sender, MouseButtonEventArgs e)
+        protected override void OnMouseDown(MouseButtonEventArgs e)
         {
-            ItemContainer? itemContainer = sender as ItemContainer;
-            NodifyEditor? editor = sender as NodifyEditor ?? itemContainer?.Editor;
-
-            if (editor?.DataContext is CalculatorViewModel calculator)
+            if (CloseGesture.Matches(e.Source, e))
             {
-                calculator.OperationsMenu.Close();
+                ViewModel.Close();
             }
         }
+    }
+
+    public partial class EditorView : UserControl
+    {
+        public EditorView()
+        {
+            InitializeComponent();
+        }
+
+        static EditorView()
+        {
+            InputProcessor.Shared<NodifyEditor>.RegisterHandlerFactory(editor => new OperationsMenuHandler(editor));
+
+            // Ensure the selecting handler is executed after the OperationsMenuHandler, otherwise left click events will not be received.
+            InputProcessor.Shared<NodifyEditor>.RemoveHandlerFactory<EditorState.Selecting>();
+            InputProcessor.Shared<NodifyEditor>.RegisterHandlerFactory(editor => new EditorState.Selecting(editor));
+        }
 
         private void OnDropNode(object sender, DragEventArgs e)
         {
-            if(e.Source is NodifyEditor editor && editor.DataContext is CalculatorViewModel calculator
+            if (e.Source is NodifyEditor editor && editor.DataContext is CalculatorViewModel calculator
                 && e.Data.GetData(typeof(OperationInfoViewModel)) is OperationInfoViewModel operation)
             {
                 OperationViewModel op = OperationFactory.GetOperation(operation);
@@ -49,8 +64,8 @@ private void OnDropNode(object sender, DragEventArgs e)
 
         private void OnNodeDrag(object sender, MouseEventArgs e)
         {
-            if(e.LeftButton == MouseButtonState.Pressed && ((FrameworkElement)sender).DataContext is OperationInfoViewModel operation)
-            { 
+            if (e.LeftButton == MouseButtonState.Pressed && ((FrameworkElement)sender).DataContext is OperationInfoViewModel operation)
+            {
                 var data = new DataObject(typeof(OperationInfoViewModel), operation);
                 DragDrop.DoDragDrop(this, data, DragDropEffects.Copy);
             }

Nodify/Connections/LineConnection.cs

@@ -68,7 +68,7 @@ protected override void DrawDefaultArrowhead(StreamGeometryContext context, Poin
             }
             else
             {
-                DrawDefaultArrowhead(context, source, target, arrowDirection, orientation);
+                base.DrawDefaultArrowhead(context, source, target, arrowDirection, orientation);
             }
         }
 

Nodify/Connectors/Connector.cs

@@ -172,6 +172,9 @@ static Connector()
         public Connector()
         {
             InputProcessor.AddSharedHandlers(this);
+
+            Loaded += OnConnectorLoaded;
+            Unloaded += OnConnectorUnloaded;
         }
 
         /// <inheritdoc />
@@ -181,9 +184,6 @@ public override void OnApplyTemplate()
 
             Container = this.GetParentOfType<ItemContainer>();
             Editor = Container?.Editor ?? this.GetParentOfType<NodifyEditor>();
-
-            Loaded += OnConnectorLoaded;
-            Unloaded += OnConnectorUnloaded;
         }
 
         #region Update Anchor

Nodify/Connectors/PendingConnection.cs

@@ -248,6 +248,13 @@ public override void OnApplyTemplate()
         {
             base.OnApplyTemplate();
 
+            if(Editor != null)
+            {
+                Editor.RemoveHandler(Connector.PendingConnectionStartedEvent, new PendingConnectionEventHandler(OnPendingConnectionStarted));
+                Editor.RemoveHandler(Connector.PendingConnectionDragEvent, new PendingConnectionEventHandler(OnPendingConnectionDrag));
+                Editor.RemoveHandler(Connector.PendingConnectionCompletedEvent, new PendingConnectionEventHandler(OnPendingConnectionCompleted));
+            }
+
             Editor = this.GetParentOfType<NodifyEditor>();
 
             if (Editor != null)

Nodify/Editor/NodifyEditor.Panning.cs

@@ -203,19 +203,25 @@ private void HandleAutoPanning(object? sender, EventArgs e)
         /// <param name="shouldDisable">Whether to enable or disable auto panning.</param>
         private void OnDisableAutoPanningChanged(bool shouldDisable)
         {
-            if (shouldDisable)
+            ClearTimer();
+            if (!shouldDisable)
             {
-                _autoPanningTimer?.Stop();
-            }
-            else if (_autoPanningTimer == null)
-            {
-                _autoPanningTimer = new DispatcherTimer(TimeSpan.FromMilliseconds(AutoPanningTickRate),
-                    DispatcherPriority.Background, HandleAutoPanning, Dispatcher);
+                _autoPanningTimer = new DispatcherTimer(DispatcherPriority.Background, Dispatcher)
+                {
+                    Interval = TimeSpan.FromMilliseconds(AutoPanningTickRate)
+                };
+                _autoPanningTimer.Tick += HandleAutoPanning;
+                _autoPanningTimer.Start();
             }
-            else
+
+            void ClearTimer()
             {
-                _autoPanningTimer.Interval = TimeSpan.FromMilliseconds(AutoPanningTickRate);
-                _autoPanningTimer.Start();
+                if (_autoPanningTimer != null)
+                {
+                    _autoPanningTimer.Stop();
+                    _autoPanningTimer.Tick -= HandleAutoPanning;
+                    _autoPanningTimer = null;
+                }
             }
         }
 

Nodify/Editor/NodifyEditor.cs

@@ -573,6 +573,8 @@ public NodifyEditor()
             SetValue(ViewportTransformPropertyKey, transform);
 
             InputProcessor.AddSharedHandlers(this);
+
+            Unloaded += OnEditorUnloaded;
         }
 
         /// <inheritdoc />
@@ -586,6 +588,11 @@ public override void OnApplyTemplate()
             OnDisableAutoPanningChanged(DisableAutoPanning);
         }
 
+        private void OnEditorUnloaded(object sender, RoutedEventArgs e)
+        {
+            OnDisableAutoPanningChanged(true);
+        }
+
         /// <inheritdoc />
         protected override DependencyObject GetContainerForItemOverride()
             => new ItemContainer(this)