[mac] Update name header for single column

This also fixes a wasteful instance being created for the facade and should
fix reuse of it.

4 files changed, 109 insertions, 155 deletions

diff --git a/Xamarin.PropertyEditing.Mac/Controls/PanelHeaderEditorControl.cs b/Xamarin.PropertyEditing.Mac/Controls/PanelHeaderEditorControl.cs
index 6cdbf15..65ff1d9 100644
--- a/Xamarin.PropertyEditing.Mac/Controls/PanelHeaderEditorControl.cs
+++ b/Xamarin.PropertyEditing.Mac/Controls/PanelHeaderEditorControl.cs
@@ -1,44 +1,50 @@
 using System;
-using System.Collections;
 using System.ComponentModel;
 using System.IO;
+
 using AppKit;
+
 using Xamarin.PropertyEditing.Mac.Resources;
 using Xamarin.PropertyEditing.ViewModels;
 
 namespace Xamarin.PropertyEditing.Mac
 {
-	internal class PanelHeaderLabelControl : NSView
+	internal class PanelHeaderEditorControl
+		: NSView
 	{
-		public const string PanelHeaderLabelIdentifierString = "PanelHeaderLabelIdentifier";
-
-		private NSImageView propertyIcon;
+		public PanelHeaderEditorControl ()
+		{
+			NSControlSize controlSize = NSControlSize.Small;
+			TranslatesAutoresizingMaskIntoConstraints = false;
 
-		private PanelViewModel viewModel;
+			this.propertyObjectName = new NSTextField {
+				ControlSize = controlSize,
+				PlaceholderString = LocalizationResources.ObjectNamePlaceholder,
+				TranslatesAutoresizingMaskIntoConstraints = false,
+			};
 
-		public PanelHeaderLabelControl (PanelViewModel viewModel)
-		{
-			if (viewModel == null)
-				throw new ArgumentNullException (nameof (viewModel));
+			this.propertyObjectName.Activated += OnObjectNameEdited;
 
-			this.viewModel = viewModel;
-			this.viewModel.PropertyChanged += ViewModel_PropertyChanged;
+			AddSubview (this.propertyObjectName);
 
-			Identifier = PanelHeaderLabelIdentifierString;
+			this.typeDisplay = new UnfocusableTextField {
+				TranslatesAutoresizingMaskIntoConstraints = false,
+			};
+			AddSubview (this.typeDisplay);
 
-			var propertyObjectNameLabel = new UnfocusableTextField {
+			this.objectNameLabel = new UnfocusableTextField {
 				Alignment = NSTextAlignment.Right,
 				StringValue = Properties.Resources.Name + ":",
 				TranslatesAutoresizingMaskIntoConstraints = false,
 			};
-			AddSubview (propertyObjectNameLabel);
+			AddSubview (this.objectNameLabel);
 
-			var propertyTypeNameLabel = new UnfocusableTextField {
+			this.typeLabel = new UnfocusableTextField {
 				Alignment = NSTextAlignment.Right,
 				StringValue = Properties.Resources.Type + ":",
 				TranslatesAutoresizingMaskIntoConstraints = false,
 			};
-			AddSubview (propertyTypeNameLabel);
+			AddSubview (this.typeLabel);
 
 			this.propertyIcon = new NSImageView {
 				ImageScaling = NSImageScale.AxesIndependently,
@@ -46,149 +52,94 @@ namespace Xamarin.PropertyEditing.Mac
 			};
 			AddSubview (this.propertyIcon);
 
-			this.DoConstraints (new NSLayoutConstraint[] {
-				propertyObjectNameLabel.ConstraintTo(this, (ol, c) => ol.Top == c.Top),
-				propertyObjectNameLabel.ConstraintTo(this, (ol, c) => ol.Left == c.Left + 182),
-				propertyObjectNameLabel.ConstraintTo(this, (ol, c) => ol.Width == 40),
-				propertyObjectNameLabel.ConstraintTo(this, (ol, c) => ol.Height == PropertyEditorControl.DefaultControlHeight),
-
-				propertyTypeNameLabel.ConstraintTo(this, (tl, c) => tl.Top == c.Top + 22),
-				propertyTypeNameLabel.ConstraintTo(this, (tl, c) => tl.Left == c.Left + 182),
-				propertyTypeNameLabel.ConstraintTo(this, (tl, c) => tl.Width == 40),
-				propertyTypeNameLabel.ConstraintTo(this, (tl, c) => tl.Height == PropertyEditorControl.DefaultControlHeight),
-
-				this.propertyIcon.ConstraintTo(this, (ico, c) => ico.Top == c.Top + 5),
-				this.propertyIcon.ConstraintTo(this, (ico, c) => ico.Left == c.Left + 32),
-				this.propertyIcon.ConstraintTo(this, (ico, c) => ico.Width == 32),
-				this.propertyIcon.ConstraintTo(this, (ico, c) => ico.Height == 32),
-			});
+			this.AddConstraints (new[] {
 
-			UpdateIcon ();
-		}
+				NSLayoutConstraint.Create (this.propertyIcon, NSLayoutAttribute.Width, NSLayoutRelation.Equal, 1, 32),
+				NSLayoutConstraint.Create (this.propertyIcon, NSLayoutAttribute.Height, NSLayoutRelation.Equal, 1, 32),
+				NSLayoutConstraint.Create (this.propertyIcon, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this, NSLayoutAttribute.Top, 1, 5),
+				NSLayoutConstraint.Create (this.propertyIcon, NSLayoutAttribute.Left, NSLayoutRelation.Equal, this, NSLayoutAttribute.Left, 1, 32),
 
-		private async void UpdateIcon ()
-		{
-			Stream icon = await this.viewModel.GetIconAsync ();
+				NSLayoutConstraint.Create (this.objectNameLabel, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this, NSLayoutAttribute.Top, 1, 5),
+				NSLayoutConstraint.Create (this.objectNameLabel, NSLayoutAttribute.Right, NSLayoutRelation.Equal, this, NSLayoutAttribute.Right, .38196601125f, 0f),
 
-			if (icon != null)
-				this.propertyIcon.Image = NSImage.FromStream (icon);
+				NSLayoutConstraint.Create (this.propertyObjectName, NSLayoutAttribute.CenterY, NSLayoutRelation.Equal, this.objectNameLabel, NSLayoutAttribute.CenterY, 1, 0),
+				NSLayoutConstraint.Create (this.propertyObjectName, NSLayoutAttribute.Left, NSLayoutRelation.Equal, this.objectNameLabel, NSLayoutAttribute.Right, 1, 5),
+				NSLayoutConstraint.Create (this.propertyObjectName, NSLayoutAttribute.Right, NSLayoutRelation.Equal, this, NSLayoutAttribute.Right, 1, -(14 + PropertyButton.DefaultSize)),
 
-			this.propertyIcon.Hidden = (icon == null);
-		}
+				NSLayoutConstraint.Create (this.typeLabel, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this.propertyObjectName, NSLayoutAttribute.Bottom, 1, 5),
+				NSLayoutConstraint.Create (this.typeLabel, NSLayoutAttribute.Right, NSLayoutRelation.Equal, this, NSLayoutAttribute.Right, .38196601125f, 0f),
 
-		void ViewModel_PropertyChanged (object sender, PropertyChangedEventArgs e)
-		{
-			if (e.PropertyName == nameof (PanelViewModel.TypeName)) {
-				UpdateIcon ();
-			}
+				NSLayoutConstraint.Create (this.typeDisplay, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this.typeLabel, NSLayoutAttribute.Top, 1, 0),
+				NSLayoutConstraint.Create (this.typeDisplay, NSLayoutAttribute.Width, NSLayoutRelation.Equal, this.propertyObjectName, NSLayoutAttribute.Width, 1, 0),
+				NSLayoutConstraint.Create (this.typeDisplay, NSLayoutAttribute.Left, NSLayoutRelation.Equal, this.typeLabel, NSLayoutAttribute.Right, 1, 5)
+			});
 		}
-	}
-
-	internal class PanelHeaderEditorControl : PropertyEditorControl
-	{
-		private NSTextField propertyObjectName;
-
-		private PanelViewModel viewModel;
 
-		public PanelHeaderEditorControl (PanelViewModel viewModel)
+		public PanelViewModel ViewModel
 		{
-			if (viewModel == null)
-				throw new ArgumentNullException (nameof (viewModel));
+			get { return this.viewModel; }
+			set {
+				if (this.viewModel == value)
+					return;
 
-			this.viewModel = viewModel;
-			this.viewModel.PropertyChanged += ViewModel_PropertyChanged;
-
-			NSControlSize controlSize = NSControlSize.Small;
-			TranslatesAutoresizingMaskIntoConstraints = false;
+				if (this.viewModel != null) {
+					this.viewModel.PropertyChanged -= OnViewModelPropertyChanged;
+				}
 
-			this.propertyObjectName = new NSTextField {
-				ControlSize = controlSize,
-				Font = NSFont.FromFontName (DefaultFontName, DefaultFontSize),
-				PlaceholderString = LocalizationResources.ObjectNamePlaceholder,
-				TranslatesAutoresizingMaskIntoConstraints = false,
-			};
+				this.viewModel = value;
+				if (this.viewModel != null)
+					this.viewModel.PropertyChanged += OnViewModelPropertyChanged;
 
-			this.propertyObjectName.Activated += PropertyObjectName_Activated;
-
-			AddSubview (this.propertyObjectName);
-
-			var propertyTypeName = new UnfocusableTextField {
-				StringValue = viewModel.TypeName,
-				TranslatesAutoresizingMaskIntoConstraints = false,
-			};
-			AddSubview (propertyTypeName);
-
-			this.DoConstraints (new NSLayoutConstraint[] {
-				this.propertyObjectName.ConstraintTo(this, (on, c) => on.Top == c.Top + 2),
-				this.propertyObjectName.ConstraintTo(this, (on, c) => on.Left == c.Left + 4),
-				this.propertyObjectName.ConstraintTo(this, (on, c) => on.Width == c.Width - 34),
-				this.propertyObjectName.ConstraintTo(this, (on, c) => on.Height == DefaultControlHeight - 3),
-
-				propertyTypeName.ConstraintTo(this, (tn, c) => tn.Top == c.Top + 22),
-				propertyTypeName.ConstraintTo(this, (tn, c) => tn.Left == c.Left + 4),
-				propertyTypeName.ConstraintTo(this, (tn, c) => tn.Width == c.Width - 34),
-				propertyTypeName.ConstraintTo(this, (tn, c) => tn.Height == DefaultControlHeight),
-			});
-
-			// We won't enable or show the PropertyButton for the header
-			this.PropertyButton.Enabled = false;
-			this.PropertyButton.Hidden = true;
-
-			UpdateValue ();
+				this.typeDisplay.StringValue = value?.TypeName ?? String.Empty;
+				UpdateValue ();
+				UpdateIcon ();
+				this.propertyObjectName.Editable = !this.viewModel.IsObjectNameReadOnly;
+			}
 		}
 
-		void PropertyObjectName_Activated (object sender, EventArgs e)
+		public void SetNextKeyView (NSView nextKeyView)
 		{
-			this.viewModel.ObjectName = this.propertyObjectName.StringValue;
+			this.propertyObjectName.NextKeyView = nextKeyView;
 		}
 
-		public override NSView FirstKeyView => this.propertyObjectName;
-
-		public override NSView LastKeyView => this.propertyObjectName;
+		private NSImageView propertyIcon;
+		private NSTextField propertyObjectName;
+		private UnfocusableTextField typeLabel, typeDisplay, objectNameLabel;
 
-		protected override void HandleErrorsChanged (object sender, DataErrorsChangedEventArgs e)
-		{
-			UpdateErrorsDisplayed (viewModel.GetErrors (viewModel.GetType ().Name));
-		}
+		private PanelViewModel viewModel;
 
-		protected override void SetEnabled ()
+		private void OnViewModelPropertyChanged (object sender, PropertyChangedEventArgs e)
 		{
-			this.propertyObjectName.Editable = !this.viewModel.IsObjectNameReadOnly;
+			if (e.PropertyName == nameof (PanelViewModel.ObjectName)) {
+				UpdateValue ();
+			} else if (e.PropertyName == nameof (PanelViewModel.TypeName)) {
+				UpdateIcon ();
+			} else if (String.IsNullOrEmpty (e.PropertyName)) {
+				UpdateValue ();
+				UpdateIcon ();
+			}
 		}
 
-		protected override void UpdateAccessibilityValues ()
+		private void UpdateValue ()
 		{
+			this.propertyObjectName.StringValue = this.viewModel.ObjectName ?? string.Empty;
 			this.propertyObjectName.AccessibilityTitle = string.Format (LocalizationResources.AccessibilityObjectName, nameof (viewModel.ObjectName));
+			this.propertyObjectName.Editable = !this.viewModel.IsObjectNameReadOnly;
 		}
 
-		protected override void UpdateErrorsDisplayed (IEnumerable errors)
+		private void OnObjectNameEdited (object sender, EventArgs e)
 		{
-			if (this.viewModel.HasErrors) {
-				SetErrors (errors);
-			} else {
-				SetErrors (null);
-				SetEnabled ();
-			}
+			this.viewModel.ObjectName = this.propertyObjectName.StringValue;
 		}
 
-		protected override void UpdateValue ()
+		private async void UpdateIcon ()
 		{
-			if (this.propertyObjectName != null) {
-				this.propertyObjectName.StringValue = this.viewModel.ObjectName ?? string.Empty;
-				this.propertyObjectName.Editable = !this.viewModel.IsObjectNameReadOnly;
-			}
-		}
+			Stream icon = await this.viewModel.GetIconAsync ();
 
-		void ViewModel_PropertyChanged (object sender, PropertyChangedEventArgs e)
-		{
-			if (e.PropertyName == nameof (PanelViewModel.ObjectName)) {
-				UpdateValue ();
-			}
-		}
+			if (icon != null)
+				this.propertyIcon.Image = NSImage.FromStream (icon);
 
-		public override nint GetHeight (EditorViewModel vm)
-		{
-			return 44;
+			this.propertyIcon.Hidden = (icon == null);
 		}
 	}
 }
diff --git a/Xamarin.PropertyEditing.Mac/Controls/PropertyEditorControl.cs b/Xamarin.PropertyEditing.Mac/Controls/PropertyEditorControl.cs
index 6e49187..46bebb8 100644
--- a/Xamarin.PropertyEditing.Mac/Controls/PropertyEditorControl.cs
+++ b/Xamarin.PropertyEditing.Mac/Controls/PropertyEditorControl.cs
@@ -72,14 +72,18 @@ namespace Xamarin.PropertyEditing.Mac
 
 			var tr = TableRow;
 			if (tr > 0) {
+				NSView view;
 				do {
 					tr--;
-					ctrl = (TableView.GetView (0, tr, false) as EditorContainer)?.EditorView?.NativeView as PropertyEditorControl;
+					view = TableView.GetView (0, tr, false);
+					ctrl = (view as EditorContainer)?.EditorView?.NativeView as PropertyEditorControl;
 				} while (tr > 0 && ctrl == null);
 
 				if (ctrl != null) {
 					ctrl.LastKeyView.NextKeyView = FirstKeyView;
 					ctrl.UpdateKeyViews ();
+				} else if (tr == 0 && view is PanelHeaderEditorControl header) {
+					header.SetNextKeyView (FirstKeyView);
 				}
 			}
 		}
diff --git a/Xamarin.PropertyEditing.Mac/PropertyTableDataSource.cs b/Xamarin.PropertyEditing.Mac/PropertyTableDataSource.cs
index 24a14cb..2334a6e 100644
--- a/Xamarin.PropertyEditing.Mac/PropertyTableDataSource.cs
+++ b/Xamarin.PropertyEditing.Mac/PropertyTableDataSource.cs
@@ -47,7 +47,7 @@ namespace Xamarin.PropertyEditing.Mac
 
 			// We only want the Header to appear at the top of both Category and Name Modes, which means item is null in both.
 			if (childIndex == 0 && item == null && !Filtering)
-				element = new PanelHeaderEditorControl (this.vm);
+				element = null;
 			else {
 				if (this.vm.ArrangeMode == PropertyArrangeMode.Name)
 					element = Filtering ? this.vm.ArrangedEditors[0][(int)childIndex] : this.vm.ArrangedEditors[0][(int)childIndex - 1];
diff --git a/Xamarin.PropertyEditing.Mac/PropertyTableDelegate.cs b/Xamarin.PropertyEditing.Mac/PropertyTableDelegate.cs
index d10439b..efd25e8 100644
--- a/Xamarin.PropertyEditing.Mac/PropertyTableDelegate.cs
+++ b/Xamarin.PropertyEditing.Mac/PropertyTableDelegate.cs
@@ -66,9 +66,6 @@ namespace Xamarin.PropertyEditing.Mac
 				return labelContainer;
 			}
 
-			if (evm == null)
-				return null;
-
 			NSView editorOrContainer = null;
 			if (this.firstCache.TryGetValue (cellIdentifier, out IEditorView editor)) {
 				this.firstCache.Remove (cellIdentifier);
@@ -92,6 +89,8 @@ namespace Xamarin.PropertyEditing.Mac
 				if (editor.IsDynamicallySized) {
 					outlineView.NoteHeightOfRowsWithIndexesChanged (new NSIndexSet (index));
 				}
+			} else if (editorOrContainer is PanelHeaderEditorControl header) {
+				header.ViewModel = this.dataSource.DataContext;
 			}
 
 			return editorOrContainer;
@@ -135,28 +134,28 @@ namespace Xamarin.PropertyEditing.Mac
 				return 20;
 
 			if (!this.registrations.TryGetValue (cellIdentifier, out EditorRegistration registration)) {
-				NSView editorOrContainer = GetEditor (cellIdentifier, vm, outlineView);
-				IEditorView view = ((editorOrContainer as EditorContainer)?.EditorView) ?? editorOrContainer as IEditorView;
-
-				if (view == null) {
-					this.registrations[cellIdentifier] = registration = new EditorRegistration {
-						RowSize = PropertyEditorControl.DefaultControlHeight
-					};
-				} else if (view.IsDynamicallySized) {
-					this.registrations[cellIdentifier] = registration = new EditorRegistration {
-						SizingInstance = view
-					};
+				registration = new EditorRegistration ();
 
-					// We're cheating by declaring GetHeight should act static, so we can call it from
-					// an instance that is being used elsewhere.
-					this.firstCache[cellIdentifier] = view;
+				if (cellIdentifier == nameof(PanelHeaderEditorControl)) {
+					registration.RowSize = 44;
 				} else {
-					this.registrations[cellIdentifier] = registration = new EditorRegistration {
-						RowSize = view.GetHeight (vm)
-					};
-
-					this.firstCache[cellIdentifier] = view;
+					NSView editorOrContainer = GetEditor (cellIdentifier, vm, outlineView);
+					IEditorView view = ((editorOrContainer as EditorContainer)?.EditorView) ?? editorOrContainer as IEditorView;
+
+					if (view == null) {
+						registration.RowSize = PropertyEditorControl.DefaultControlHeight;
+					} else if (view.IsDynamicallySized) {
+						registration.SizingInstance = view;
+					} else {
+						this.registrations[cellIdentifier] = registration = new EditorRegistration {
+							RowSize = view.GetHeight (vm)
+						};
+
+						this.firstCache[cellIdentifier] = view;
+					}
 				}
+
+				this.registrations[cellIdentifier] = registration;
 			}
 
 			return registration.GetHeight (vm);
@@ -204,7 +203,7 @@ namespace Xamarin.PropertyEditing.Mac
 
 				return new EditorContainer (editor) { Identifier = identifier };
 			} else
-				return new PanelHeaderEditorControl (this.dataSource.DataContext);
+				return new PanelHeaderEditorControl ();
 		}
 
 		private void GetVMGroupCellItendifiterFromFacade (NSObject item, out EditorViewModel vm, out IGroupingList<string, EditorViewModel> group, out string cellIdentifier)
@@ -212,7 +211,7 @@ namespace Xamarin.PropertyEditing.Mac
 			var facade = (NSObjectFacade)item;
 			vm = facade.Target as EditorViewModel;
 			group = facade.Target as IGroupingList<string, EditorViewModel>;
-			cellIdentifier = facade.Target is PanelHeaderEditorControl pvh
+			cellIdentifier = facade.Target == null
 								   ? nameof (PanelHeaderEditorControl)
 								   : (group == null) ? vm.GetType ().FullName : group.Key;
 		}