Merge pull request #164 from Dirkster99/Issue_136_CanDock

Implemented CanDock property to lock layout as descriped in #136

source/Components/AvalonDock/Controls/DragService.cs

@@ -237,11 +237,25 @@ internal void Abort()
 
 		#region Private Methods
 
+		/// <summary>
+		/// Adds <see cref="IOverlayWindowHost"/>s into a private collection of possible
+		/// drop target hosts that can show a drop target button to drop a dragged
+		/// <see cref="LayoutAnchorableFloatingWindowControl"/> or
+		/// <see cref="LayoutDocumentFloatingWindowControl"/> into it.
+		/// </summary>
 		private void GetOverlayWindowHosts()
 		{
-			_overlayWindowHosts.AddRange(_manager.GetFloatingWindowsByZOrder().OfType<LayoutAnchorableFloatingWindowControl>().Where(fw => fw != _floatingWindow && fw.IsVisible));
-			_overlayWindowHosts.AddRange(_manager.GetFloatingWindowsByZOrder().OfType<LayoutDocumentFloatingWindowControl>().Where(fw => fw != _floatingWindow && fw.IsVisible));
-			_overlayWindowHosts.Add(_manager);
+			if (_manager.Layout.RootPanel.CanDock)
+			{
+				// Add LayoutFloatingWindowControls as drop target hosts
+				// 1) Don't drop a floating window on to itself
+				// 2) Use this Drop target if its visible
+				_overlayWindowHosts.AddRange(_manager.GetFloatingWindowsByZOrder().OfType<LayoutAnchorableFloatingWindowControl>().Where(fw => fw != _floatingWindow && fw.IsVisible));
+				_overlayWindowHosts.AddRange(_manager.GetFloatingWindowsByZOrder().OfType<LayoutDocumentFloatingWindowControl>().Where(fw => fw != _floatingWindow && fw.IsVisible));
+
+				// Add dockingManager itself as a drop target host
+				_overlayWindowHosts.Add(_manager);
+			}
 		}
 
 		#endregion Private Methods

source/Components/AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs

@@ -80,6 +80,9 @@ internal LayoutAnchorableFloatingWindowControl(LayoutAnchorableFloatingWindow mo
 
 		#region Properties
 
+		/// <inheritdoc />
+		public override ILayoutElement Model => _model;
+
 		#region SingleContentLayoutItem
 
 		/// <summary><see cref="SingleContentLayoutItem"/> dependency property.</summary>
@@ -176,10 +179,6 @@ IEnumerable<IDropArea> IOverlayWindowHost.GetDropAreas(LayoutFloatingWindowContr
 		#endregion Public Methods
 
 		#region Overrides
-
-		/// <inheritdoc />
-		public override ILayoutElement Model => _model;
-
 		/// <inheritdoc />
 		protected override void OnInitialized(EventArgs e)
 		{

source/Components/AvalonDock/Controls/OverlayWindow.cs

@@ -356,6 +356,7 @@ IEnumerable<IDropTarget> IOverlayWindow.GetTargets()
 				{
 					case DropAreaType.DockingManager:
 						{
+							// Dragging over DockingManager -> Add DropTarget Area
 							var dropAreaDockingManager = visibleArea as DropArea<DockingManager>;
 							yield return new DockingManagerDropTarget(dropAreaDockingManager.AreaElement, _dockingManagerDropTargetLeft.GetScreenArea(), DropTargetType.DockingManagerDockLeft);
 							yield return new DockingManagerDropTarget(dropAreaDockingManager.AreaElement, _dockingManagerDropTargetTop.GetScreenArea(), DropTargetType.DockingManagerDockTop);
@@ -365,6 +366,7 @@ IEnumerable<IDropTarget> IOverlayWindow.GetTargets()
 						break;
 					case DropAreaType.AnchorablePane:
 						{
+							// Dragging over AnchorablePane -> Add DropTarget Area
 							var dropAreaAnchorablePane = visibleArea as DropArea<LayoutAnchorablePaneControl>;
 							yield return new AnchorablePaneDropTarget(dropAreaAnchorablePane.AreaElement, _anchorablePaneDropTargetLeft.GetScreenArea(), DropTargetType.AnchorablePaneDockLeft);
 							yield return new AnchorablePaneDropTarget(dropAreaAnchorablePane.AreaElement, _anchorablePaneDropTargetTop.GetScreenArea(), DropTargetType.AnchorablePaneDockTop);
@@ -399,6 +401,7 @@ IEnumerable<IDropTarget> IOverlayWindow.GetTargets()
 						break;
 					case DropAreaType.DocumentPane:
 						{
+							// Dragging over DocumentPane -> Add DropTarget Area
 							bool isDraggingAnchorables = _floatingWindow.Model is LayoutAnchorableFloatingWindow;
 							if (isDraggingAnchorables && _gridDocumentPaneFullDropTargets != null)
 							{
@@ -483,6 +486,7 @@ IEnumerable<IDropTarget> IOverlayWindow.GetTargets()
 						break;
 					case DropAreaType.DocumentPaneGroup:
 						{
+							// Dragging over DocumentPaneGroup -> Add DropTarget Area
 							var dropAreaDocumentPane = visibleArea as DropArea<LayoutDocumentPaneGroupControl>;
 							if (_documentPaneDropTargetInto.IsVisible)
 								yield return new DocumentPaneGroupDropTarget(dropAreaDocumentPane.AreaElement, _documentPaneDropTargetInto.GetScreenArea(), DropTargetType.DocumentPaneGroupDockInside);

source/Components/AvalonDock/Layout/LayoutAnchorable.cs

@@ -151,7 +151,9 @@ public bool CanDockAsTabbedDocument
 			}
 		}
 
-		/// <summary>Gets/sets whether a document can be dragged (to be dropped in a different location) or not. Use this property in conjunction with <see cref="CanMove"/> and <see cref="CanClose"/> to lock a document in its layout position.</summary>
+		/// <summary>Gets/sets whether a document can be dragged (to be dropped in a different location) or not.
+		/// Use this property in conjunction with <see cref="CanMove"/> and <see cref="CanClose"/> and <see cref="LayoutPanel.CanDock"/>
+		/// to lock an anchorable in its layout position.</summary>
 		public bool CanMove
 		{
 			get => _canMove;

source/Components/AvalonDock/Layout/LayoutDocument.cs

@@ -26,7 +26,9 @@ public class LayoutDocument : LayoutContent
 
 		#region Properties
 
-		/// <summary>Gets/sets whether a document can be dragged (to be dropped in a different location) or not. Use this property in conjunction with <see cref="CanMove"/> and <see cref="CanClose"/> to lock a document in its layout position.</summary>
+		/// <summary>Gets/sets whether a document can be dragged (to be dropped in a different location) or not.
+		/// Use this property in conjunction with <see cref="CanMove"/> and <see cref="CanClose"/> and <see cref="LayoutPanel.CanDock"/>
+		/// to lock a document in its layout position.</summary>
 		public bool CanMove
 		{
 			get => _canMove;

source/Components/AvalonDock/Layout/LayoutPanel.cs

@@ -11,6 +11,7 @@ This program is provided to you under the terms of the Microsoft Public
 using System.Linq;
 using System.Windows.Markup;
 using System.Windows.Controls;
+using System.Windows;
 
 namespace AvalonDock.Layout
 {
@@ -52,6 +53,32 @@ public Orientation Orientation
 			}
 		}
 
+		#region CanDock
+		/// <summary>
+		/// Using a DependencyProperty as the backing store for thhe <see cref="CanDock"/> property.
+		/// </summary>
+		public static readonly DependencyProperty CanDockProperty =
+			DependencyProperty.Register("CanDock", typeof(bool),
+				typeof(LayoutPanel), new PropertyMetadata(true));
+
+		/// <summary>
+		/// Gets/sets dependency property that determines whether docking of dragged items
+		/// is enabled or not. This property can be used disable/enable docking of
+		/// dragged FloatingWindowControls.
+		/// 
+		/// This property should only be set to false if:
+		/// <see cref="LayoutAnchorable.CanMove"/> and <see cref="LayoutDocument.CanMove"/>
+		/// are false since users will otherwise be able to:
+		/// 1) Drag an item away
+		/// 2) But won't be able to dock it agin.
+		/// </summary>
+		public bool CanDock
+		{
+			get { return (bool)GetValue(CanDockProperty); }
+			set { SetValue(CanDockProperty, value); }
+		}
+		#endregion CanDock
+
 		#endregion Properties
 
 		#region Overrides
@@ -63,14 +90,28 @@ public Orientation Orientation
 		public override void WriteXml(System.Xml.XmlWriter writer)
 		{
 			writer.WriteAttributeString(nameof(Orientation), Orientation.ToString());
+
+			if (CanDock == false)
+				writer.WriteAttributeString(nameof(CanDock), CanDock.ToString());
+
 			base.WriteXml(writer);
 		}
 
 		/// <inheritdoc />
+		/// <summary>
+		/// This method is never invoked - <see cref="LayoutRoot"/>.ReadRootPanel()
+		/// for implementation of this reader.
+		/// </summary>
 		public override void ReadXml(System.Xml.XmlReader reader)
 		{
 			if (reader.MoveToAttribute(nameof(Orientation)))
 				Orientation = (Orientation)Enum.Parse(typeof(Orientation), reader.Value, true);
+			if (reader.MoveToAttribute(nameof(CanDock)))
+			{
+				var canDockStr = reader.GetAttribute("CanDock");
+				if (canDockStr != null)
+					CanDock = bool.Parse(canDockStr);
+			}
 			base.ReadXml(reader);
 		}
 

source/Components/AvalonDock/Layout/LayoutRoot.cs

@@ -548,10 +548,10 @@ void IXmlSerializable.ReadXml(XmlReader reader)
 				return;
 			}
 
-			var layoutPanelElements = ReadRootPanel(reader, out var orientation);
+			var layoutPanelElements = ReadRootPanel(reader, out var orientation, out var canDock);
 			if (layoutPanelElements != null)
 			{
-				RootPanel = new LayoutPanel { Orientation = orientation };
+				RootPanel = new LayoutPanel { Orientation = orientation, CanDock = canDock };
 				//Add all children to RootPanel
 				foreach (var panel in layoutPanelElements) RootPanel.Children.Add(panel);
 			}
@@ -786,9 +786,20 @@ private void FillLayoutAnchorSide(XmlReader reader, LayoutAnchorSide layoutAncho
 			}
 		}
 
-		private List<ILayoutPanelElement> ReadRootPanel(XmlReader reader, out Orientation orientation)
+		/// <summary>
+		/// Reads all properties of the <see cref="LayoutPanel"/> and returns them.
+		/// </summary>
+		/// <param name="reader"></param>
+		/// <param name="orientation"></param>
+		/// <param name="canDock"></param>
+		/// <returns></returns>
+		private List<ILayoutPanelElement> ReadRootPanel(XmlReader reader
+			, out Orientation orientation
+			, out bool canDock)
 		{
 			orientation = Orientation.Horizontal;
+			canDock = true;
+
 			var result = new List<ILayoutPanelElement>();
 			var startElementName = reader.LocalName;
 			reader.Read();
@@ -799,6 +810,11 @@ private List<ILayoutPanelElement> ReadRootPanel(XmlReader reader, out Orientatio
 			if (reader.LocalName.Equals(nameof(RootPanel)))
 			{
 				orientation = (Orientation)Enum.Parse(typeof(Orientation),reader.GetAttribute(nameof(Orientation)), true);
+
+				var canDockStr = reader.GetAttribute("CanDock");
+				if (canDockStr != null)
+					canDock = bool.Parse(canDockStr);
+
 				reader.Read();
 				while (true)
 				{