modify code

source/AvalonDocPanelMemoryLeaks/MainWindow.xaml.cs

@@ -34,8 +34,10 @@ private void Button_Click(object sender, RoutedEventArgs e)
             UserControl content = new UserControl();
             HeavyLoad = new HeavyLoad();
             content.DataContext = HeavyLoad;
-            LayoutDocument docDocument = new LayoutDocument();
-            docDocument.Content = content;
+            LayoutDocument docDocument = new LayoutDocument
+            {
+                Content = content
+            };
             docGrup.Children.Add(docDocument);
             docDocument.Closed += DocClosed;
         }

source/Components/AvalonDock/Controls/Extensions.cs

@@ -28,8 +28,8 @@ public static IEnumerable<T> FindVisualChildren<T>(this DependencyObject depObj)
 			for (var i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
 			{
 				var child = VisualTreeHelper.GetChild(depObj, i);
-				if (child is T)
-					yield return (T) child;
+				if (child is T t)
+					yield return t;
 				foreach (var childOfChild in FindVisualChildren<T>(child))
 					yield return childOfChild;
 			}
@@ -45,8 +45,8 @@ public static IEnumerable<T> FindLogicalChildren<T>(this DependencyObject depObj
 			if (depObj == null) yield break;
 			foreach (var child in LogicalTreeHelper.GetChildren(depObj).OfType<DependencyObject>())
 			{
-				if (child is T)
-					yield return (T) child;
+				if (child is T t)
+					yield return t;
 				foreach (var childOfChild in FindLogicalChildren<T>(child))
 					yield return childOfChild;
 			}

source/Components/AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs

@@ -31,7 +31,7 @@ namespace AvalonDock.Controls
 	public class LayoutAnchorableFloatingWindowControl : LayoutFloatingWindowControl, IOverlayWindowHost
 	{
 		#region fields
-		private LayoutAnchorableFloatingWindow _model;
+		private readonly LayoutAnchorableFloatingWindow _model;
 		private OverlayWindow _overlayWindow = null;
 		private List<IDropArea> _dropAreas = null;
 		#endregion fields

source/Components/AvalonDock/Controls/LayoutAnchorablePaneControl.cs

@@ -26,7 +26,7 @@ namespace AvalonDock.Controls
 	public class LayoutAnchorablePaneControl : TabControlEx, ILayoutControl//, ILogicalChildrenContainer
 	{
 		#region fields
-		private LayoutAnchorablePane _model;
+		private readonly LayoutAnchorablePane _model;
 		#endregion fields
 
 		#region Constructors

source/Components/AvalonDock/Controls/LayoutAutoHideWindowControl.cs

@@ -34,7 +34,7 @@ public class LayoutAutoHideWindowControl : HwndHost, ILayoutControl
 		private LayoutAnchorable _model;
 		private HwndSource _internalHwndSource = null;
 		private IntPtr parentWindowHandle;
-		private ContentPresenter _internalHostPresenter = new ContentPresenter();
+		private readonly ContentPresenter _internalHostPresenter = new ContentPresenter();
 		private Grid _internalGrid = null;
 		private AnchorSide _side;
 		private LayoutGridResizerControl _resizer = null;

source/Components/AvalonDock/Controls/LayoutDocumentPaneControl.cs

@@ -29,7 +29,7 @@ namespace AvalonDock.Controls
 	public class LayoutDocumentPaneControl : TabControlEx, ILayoutControl//, ILogicalChildrenContainer
 	{
 		#region fields
-		private LayoutDocumentPane _model;
+		private readonly LayoutDocumentPane _model;
 		#endregion fields
 
 		#region Constructors

source/Components/AvalonDock/Controls/LayoutDocumentPaneGroupControl.cs

@@ -22,7 +22,7 @@ namespace AvalonDock.Controls
 	public class LayoutDocumentPaneGroupControl : LayoutGridControl<ILayoutDocumentPane>, ILayoutControl
 	{
 		#region fields
-		private LayoutDocumentPaneGroup _model;
+		private readonly LayoutDocumentPaneGroup _model;
 		#endregion fields
 
 		#region Constructors

source/Components/AvalonDock/Controls/LayoutGridControl.cs

@@ -34,11 +34,11 @@ namespace AvalonDock.Controls
 	public abstract class LayoutGridControl<T> : Grid, ILayoutControl, IAdjustableSizeLayout where T : class, ILayoutPanelElement
 	{
 		#region fields
-		private LayoutPositionableGroup<T> _model;
-		private Orientation _orientation;
+		private readonly LayoutPositionableGroup<T> _model;
+		private readonly Orientation _orientation;
 		private bool _initialized;
 		private ChildrenTreeChange? _asyncRefreshCalled;
-		private ReentrantFlag _fixingChildrenDockLengths = new ReentrantFlag();
+		private readonly ReentrantFlag _fixingChildrenDockLengths = new ReentrantFlag();
 		private Border _resizerGhost = null;
 		private Window _resizerWindowHost = null;
 		private Vector _initialStartPoint;

source/Components/AvalonDock/Controls/LayoutItem.cs

@@ -39,8 +39,8 @@ public abstract class LayoutItem : FrameworkElement
 		private ICommand _defaultMoveToNextTabGroupCommand;
 		private ICommand _defaultMoveToPreviousTabGroupCommand;
 		private ContentPresenter _view = null;
-		private ReentrantFlag _isSelectedReentrantFlag = new ReentrantFlag();
-		private ReentrantFlag _isActiveReentrantFlag = new ReentrantFlag();
+		private readonly ReentrantFlag _isSelectedReentrantFlag = new ReentrantFlag();
+		private readonly ReentrantFlag _isActiveReentrantFlag = new ReentrantFlag();
 		#endregion fields
 
 		#region Constructors

source/Components/AvalonDock/Controls/LayoutPanelControl.cs

@@ -21,7 +21,7 @@ namespace AvalonDock.Controls
 	public class LayoutPanelControl : LayoutGridControl<ILayoutPanelElement>, ILayoutControl
 	{
 		#region fields
-		private LayoutPanel _model;
+		private readonly LayoutPanel _model;
 		#endregion fields
 
 		#region Constructors
@@ -41,34 +41,29 @@ protected override void OnFixChildrenDockLengths()
 		{
 			if (ActualWidth == 0.0 || ActualHeight == 0.0) return;
 
-			var modelAsPositionableElement = _model as ILayoutPositionableElementWithActualSize;
-			#region Setup DockWidth/Height for children
-			if (_model.Orientation == Orientation.Horizontal)
+            #region Setup DockWidth/Height for children
+            if (_model.Orientation == Orientation.Horizontal)
 			{
 				if (_model.ContainsChildOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>())
 				{
 					for (var i = 0; i < _model.Children.Count; i++)
 					{
-						var childContainerModel = _model.Children[i] as ILayoutContainer;
-						var childPositionableModel = _model.Children[i] as ILayoutPositionableElement;
-
-						if (childContainerModel != null &&
-							(childContainerModel.IsOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>() ||
-							 childContainerModel.ContainsChildOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>()))
+                        if (_model.Children[i] as ILayoutContainer != null &&
+							((_model.Children[i] as ILayoutContainer).IsOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>() ||
+                             (_model.Children[i] as ILayoutContainer).ContainsChildOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>()))
 						{
 							// Keep set values (from XML for instance)
-							if(!childPositionableModel.DockWidth.IsStar) childPositionableModel.DockWidth = new GridLength(1.0, GridUnitType.Star);
+							if(!(_model.Children[i] as ILayoutPositionableElement).DockWidth.IsStar) (_model.Children[i] as ILayoutPositionableElement).DockWidth = new GridLength(1.0, GridUnitType.Star);
 						}
-						else if (childPositionableModel != null && childPositionableModel.DockWidth.IsStar)
+						else if (_model.Children[i] as ILayoutPositionableElement != null && (_model.Children[i] as ILayoutPositionableElement).DockWidth.IsStar)
 						{
-							var childPositionableModelWidthActualSize = childPositionableModel as ILayoutPositionableElementWithActualSize;
-							var childDockMinWidth = childPositionableModel.CalculatedDockMinWidth();
+							var childPositionableModelWidthActualSize = _model.Children[i] as ILayoutPositionableElement as ILayoutPositionableElementWithActualSize;
+							var childDockMinWidth = (_model.Children[i] as ILayoutPositionableElement).CalculatedDockMinWidth();
 							var widthToSet = Math.Max(childPositionableModelWidthActualSize.ActualWidth, childDockMinWidth);
 
 							widthToSet = Math.Min(widthToSet, ActualWidth / 2.0);
 							widthToSet = Math.Max(widthToSet, childDockMinWidth);
-
-							childPositionableModel.DockWidth = new GridLength(widthToSet, GridUnitType.Pixel);
+                            (_model.Children[i] as ILayoutPositionableElement).DockWidth = new GridLength(widthToSet, GridUnitType.Pixel);
 						}
 					}
 				}
@@ -91,25 +86,21 @@ protected override void OnFixChildrenDockLengths()
 				{
 					for (var i = 0; i < _model.Children.Count; i++)
 					{
-						var childContainerModel = _model.Children[i] as ILayoutContainer;
-						var childPositionableModel = _model.Children[i] as ILayoutPositionableElement;
-
-						if (childContainerModel != null &&
+                        if (_model.Children[i] is ILayoutContainer childContainerModel &&
 							(childContainerModel.IsOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>() ||
 							 childContainerModel.ContainsChildOfType<LayoutDocumentPane, LayoutDocumentPaneGroup>()))
 						{
 							// Keep set values (from XML for instance)
-							if(!childPositionableModel.DockHeight.IsStar) childPositionableModel.DockHeight = new GridLength(1.0, GridUnitType.Star);
+							if(!(_model.Children[i] as ILayoutPositionableElement).DockHeight.IsStar) (_model.Children[i] as ILayoutPositionableElement).DockHeight = new GridLength(1.0, GridUnitType.Star);
 						}
-						else if (childPositionableModel != null && childPositionableModel.DockHeight.IsStar)
+						else if (_model.Children[i] as ILayoutPositionableElement != null && (_model.Children[i] as ILayoutPositionableElement).DockHeight.IsStar)
 						{
-							var childPositionableModelWidthActualSize = childPositionableModel as ILayoutPositionableElementWithActualSize;
-							var childDockMinHeight = childPositionableModel.CalculatedDockMinHeight();
+							var childPositionableModelWidthActualSize = _model.Children[i] as ILayoutPositionableElement as ILayoutPositionableElementWithActualSize;
+							var childDockMinHeight = (_model.Children[i] as ILayoutPositionableElement).CalculatedDockMinHeight();
 							var heightToSet = Math.Max(childPositionableModelWidthActualSize.ActualHeight, childDockMinHeight);
 							heightToSet = Math.Min(heightToSet, ActualHeight / 2.0);
 							heightToSet = Math.Max(heightToSet, childDockMinHeight);
-
-							childPositionableModel.DockHeight = new GridLength(heightToSet, GridUnitType.Pixel);
+                            (_model.Children[i] as ILayoutPositionableElement).DockHeight = new GridLength(heightToSet, GridUnitType.Pixel);
 						}
 					}
 				}

source/Components/AvalonDock/Controls/Shell/Standard/NativeMethods.cs

@@ -1907,9 +1907,11 @@ public static NONCLIENTMETRICS VistaMetricsStruct
 		{
 			get
 			{
-				var ncm = new NONCLIENTMETRICS();
-				ncm.cbSize = Marshal.SizeOf(typeof(NONCLIENTMETRICS));
-				return ncm;
+                var ncm = new NONCLIENTMETRICS
+                {
+                    cbSize = Marshal.SizeOf(typeof(NONCLIENTMETRICS))
+                };
+                return ncm;
 			}
 		}
 
@@ -1918,10 +1920,12 @@ public static NONCLIENTMETRICS XPMetricsStruct
 		{
 			get
 			{
-				var ncm = new NONCLIENTMETRICS();
-				// Account for the missing iPaddedBorderWidth
-				ncm.cbSize = Marshal.SizeOf(typeof(NONCLIENTMETRICS)) - sizeof(int);
-				return ncm;
+                var ncm = new NONCLIENTMETRICS
+                {
+                    // Account for the missing iPaddedBorderWidth
+                    cbSize = Marshal.SizeOf(typeof(NONCLIENTMETRICS)) - sizeof(int)
+                };
+                return ncm;
 			}
 		}
 	}

source/Components/AvalonDock/Layout/LayoutDocumentPane.cs

@@ -29,7 +29,7 @@ public class LayoutDocumentPane : LayoutPositionableGroup<LayoutContent>, ILayou
 		string _id;
 
 		[XmlIgnore]
-		bool _autoFixSelectedContent = true;
+        readonly bool _autoFixSelectedContent = true;
 		#endregion fields
 
 		#region Constructors
@@ -111,7 +111,7 @@ public IEnumerable<LayoutContent> ChildrenSorted
 		protected override bool GetVisibility()
 		{
 			if (Parent is LayoutDocumentPaneGroup)
-				return ChildrenCount > 0 && Children.Any(c => c is LayoutDocument && ((LayoutDocument)c).IsVisible || c is LayoutAnchorable);
+				return ChildrenCount > 0 && Children.Any(c => (c is LayoutDocument document && document.IsVisible) || c is LayoutAnchorable);
 			return true;
 		}
 
@@ -200,9 +200,8 @@ public override void ConsoleDump(int tab)
 		/// <returns></returns>
 		public int IndexOf(LayoutContent content)
 		{
-			var documentChild = content as LayoutDocument;
-			return documentChild == null ? -1 : Children.IndexOf(documentChild);
-		}
+            return !(content is LayoutDocument documentChild) ? -1 : Children.IndexOf(documentChild);
+        }
 
 		/// <summary>Invalidates the current <see cref="SelectedContentIndex"/> and sets the index for the next avialable child with IsEnabled == true.</summary>
 		internal void SetNextSelectedIndex()

source/Components/AvalonDock/Layout/LayoutGroup.cs

@@ -25,7 +25,7 @@ namespace AvalonDock.Layout
 	public abstract class LayoutGroup<T> : LayoutGroupBase, ILayoutGroup, IXmlSerializable where T : class, ILayoutElement
 	{
 		#region fields
-		private ObservableCollection<T> _children = new ObservableCollection<T>();
+		private readonly ObservableCollection<T> _children = new ObservableCollection<T>();
 		private bool _isVisible = true;
 		#endregion fields
 

source/MLibTest/MLibTest/Demos/ViewModels/WorkSpaceViewModel.cs

@@ -93,7 +93,7 @@ public string DisplayName
 	internal class WorkSpaceViewModel : MLibTest.ViewModels.Base.ViewModelBase, IWorkSpaceViewModel
 	{
 		#region fields
-		private ObservableCollection<DocumentViewModel> _files = new ObservableCollection<DocumentViewModel>();
+		private readonly ObservableCollection<DocumentViewModel> _files = new ObservableCollection<DocumentViewModel>();
 		private ToolViewModel[] _tools = null;
 
 		private ICommand _openCommand = null;
@@ -138,9 +138,8 @@ public DocumentViewModel ActiveDocument
 					_activeDocument = value;
 					RaisePropertyChanged(nameof(ActiveDocument));
 
-					if (ActiveDocumentChanged != null)
-						ActiveDocumentChanged(this, EventArgs.Empty);
-				}
+                    ActiveDocumentChanged?.Invoke(this, EventArgs.Empty);
+                }
 			}
 		}
 

source/MLibTest/MLibTest/MainWindow.xaml.cs

@@ -170,12 +170,10 @@ internal void OnLayoutLoaded_Event(object sender, LayoutLoadedEventArgs layoutLo
 
 		internal async void OnLoadLayoutAsync(object parameter = null)
 		{
-			AppViewModel wspace = this.DataContext as AppViewModel;
-
-			if (wspace != null)
-				wspace.CloseAllDocuments();
+            if (this.DataContext is AppViewModel wspace)
+                wspace.CloseAllDocuments();
 
-			App myApp = (App)Application.Current;
+            App myApp = (App)Application.Current;
 
 			LayoutLoaderResult LoaderResult = await myApp.LayoutLoaded.GetLayoutString(OnLayoutLoaded_Event);