DYN-8308: Fix temporary connector and Node memory leak (#16198)

Author: zeusongit

src/DynamoCoreWpf/ViewModels/Core/ConnectorViewModel.cs

@@ -1204,25 +1204,32 @@ private void UpdateDynamicStrokeThickness()
         /// </summary>
         public override void Dispose()
         {
-            model.PropertyChanged -= HandleConnectorPropertyChanged;
+            if (model != null)
+            {
+                model.PropertyChanged -= HandleConnectorPropertyChanged;
+
+                model.Start.PropertyChanged -= StartPortModel_PropertyChanged;
+                model.End.PropertyChanged -= EndPortModel_PropertyChanged;
 
-            model.Start.PropertyChanged -= StartPortModel_PropertyChanged;
-            model.End.PropertyChanged -= EndPortModel_PropertyChanged;
+                model.Start.Owner.PropertyChanged -= StartOwner_PropertyChanged;
+                model.End.Owner.PropertyChanged -= EndOwner_PropertyChanged;
+                model.ConnectorPinModels.CollectionChanged -= ConnectorPinModelCollectionChanged;
 
-            model.Start.Owner.PropertyChanged -= StartOwner_PropertyChanged;
-            model.End.Owner.PropertyChanged -= EndOwner_PropertyChanged;
-            model.ConnectorPinModels.CollectionChanged -= ConnectorPinModelCollectionChanged;
+                // Nodevm and NodeEnd props are found via model
+                if (Nodevm != null)
+                {
+                    Nodevm.PropertyChanged -= nodeViewModel_PropertyChanged;
+                }
+                if (NodeEnd != null)
+                {
+                    NodeEnd.PropertyChanged -= nodeEndViewModel_PropertyChanged;
+                }
+            }
+
+            workspaceViewModel.PropertyChanged -= WorkspaceViewModel_PropertyChanged;
 
             workspaceViewModel.DynamoViewModel.PropertyChanged -= DynamoViewModel_PropertyChanged;
             workspaceViewModel.DynamoViewModel.Model.PreferenceSettings.PropertyChanged -= DynamoViewModel_PropertyChanged;
-            if (Nodevm != null)
-            {
-                Nodevm.PropertyChanged -= nodeViewModel_PropertyChanged;
-            }
-            if (NodeEnd != null)
-            {
-                NodeEnd.PropertyChanged -= nodeEndViewModel_PropertyChanged;
-            }
 
             if (ConnectorPinViewCollection != null)
             {
@@ -1235,16 +1242,14 @@ public override void Dispose()
                 }
             }
 
-            workspaceViewModel.PropertyChanged -= WorkspaceViewModel_PropertyChanged;
-
             this.PropertyChanged -= ConnectorViewModelPropertyChanged;
             DiscardAllConnectorPinModels();
 
-            if(ConnectorContextMenuViewModel != null)
+            if (ConnectorContextMenuViewModel != null)
             {
                 ConnectorContextMenuViewModel.Dispose();
             }
-            if(ConnectorAnchorViewModel != null)
+            if (ConnectorAnchorViewModel != null)
             {
                 ConnectorAnchorViewModel.Dispose();
             }

src/DynamoCoreWpf/ViewModels/Core/StateMachine.cs

@@ -332,6 +332,7 @@ internal void UpdateActiveConnector(System.Windows.Point mouseCursor)
                     foreach (ConnectorViewModel a in activeConnectors)
                     {
                         this.WorkspaceElements.Remove(a);
+                        a.Dispose();
                     }
                 }
                 this.activeConnectors = null;

src/DynamoCoreWpf/Views/Core/NodeView.xaml.cs

@@ -128,7 +128,6 @@ public NodeView()
             nodeBorder.SizeChanged += OnSizeChanged;
             DataContextChanged += OnDataContextChanged;
 
-
             Panel.SetZIndex(this, 1);
         }
 
@@ -154,6 +153,8 @@ private void OnNodeViewUnloaded(object sender, RoutedEventArgs e)
                 previewControl = null;
             }
             nodeBorder.SizeChanged -= OnSizeChanged;
+            DataContextChanged -= OnDataContextChanged;
+            Loaded -= OnNodeViewLoaded;
         }
 
         #endregion

src/DynamoCoreWpf/Views/Core/WorkspaceView.xaml.cs

@@ -1292,6 +1292,7 @@ private void OnGeometryScaling_Click(object sender, RoutedEventArgs e)
         public void Dispose()
         {
             RemoveViewModelsubscriptions(ViewModel);
+            DataContextChanged -= OnWorkspaceViewDataContextChanged;
         }
     }
 }