[mac] Fix editor panel theme handling

DynamicFillBox now allows for colors to be not found, sort of a hack fix
to deal with the fact that we allow PropertyEditorPanel to be used in
xibs, so we can't demand a IHostResourceProvider in the ctor, we have to
accept it later.

This also fixes the fact that the header theming wouldn't update when
the resource provider changes.

Author: Eric Maupin

Xamarin.PropertyEditing.Mac/Controls/Custom/DynamicFillBox.cs

@@ -8,15 +8,27 @@ internal class DynamicFillBox
 	{
 		public DynamicFillBox (IHostResourceProvider hostResources, string colorName)
 		{
-			this.hostResources = hostResources;
+			if (hostResources == null)
+				throw new ArgumentNullException (nameof (hostResources));
+
 			BorderWidth = 0;
 			BoxType = NSBoxType.NSBoxCustom;
 			TranslatesAutoresizingMaskIntoConstraints = false;
 			this.colorName = colorName;
 			if (colorName == null)
 				FillColor = NSColor.Clear;
 
-			ViewDidChangeEffectiveAppearance ();
+			HostResourceProvider = hostResources;
+		}
+
+		public IHostResourceProvider HostResourceProvider
+		{
+			get { return this.hostResources; }
+			set
+			{
+				this.hostResources = value;
+				ViewDidChangeEffectiveAppearance ();
+			}
 		}
 
 		public string FillColorName
@@ -37,10 +49,14 @@ public override void ViewDidChangeEffectiveAppearance ()
 			if (this.colorName == null)
 				return;
 
-			FillColor = this.hostResources.GetNamedColor (this.colorName);
+			NSColor color = this.hostResources.GetNamedColor (this.colorName);
+			if (color == null)
+				return;
+
+			FillColor = color;
 		}
 
-		private readonly IHostResourceProvider hostResources;
+		private IHostResourceProvider hostResources;
 		private string colorName;
 	}
 }

Xamarin.PropertyEditing.Mac/PropertyEditorPanel.cs

@@ -64,8 +64,7 @@ public IHostResourceProvider HostResourceProvider
 					throw new ArgumentNullException (nameof (value), "Cannot set HostResourceProvider to null");
 
 				this.hostResources = value;
-				if (this.propertyTable.Delegate != null)
-					this.propertyTable.Delegate = new PropertyTableDelegate (value, this.dataSource);
+				UpdateResourceProvider ();
 			}
 		}
 
@@ -139,31 +138,31 @@ public override void ViewDidChangeEffectiveAppearance ()
 
 		private NSSearchField propertyFilter;
 		private NSStackView tabStack;
+		private DynamicFillBox header, border;
 
-		// Shared initialization code
 		private void Initialize ()
 		{
 			AutoresizingMask = NSViewResizingMask.WidthSizable | NSViewResizingMask.HeightSizable;
 
 			NSControlSize controlSize = NSControlSize.Small;
 
-			var header = new DynamicFillBox (HostResourceProvider, NamedResources.PanelTabBackground) {
+			this.header = new DynamicFillBox (HostResourceProvider, NamedResources.PanelTabBackground) {
 				ContentViewMargins = new CGSize (0, 0),
 				ContentView = new NSView ()
 			};
-			AddSubview (header);
+			AddSubview (this.header);
 
-			var border = new DynamicFillBox (HostResourceProvider, NamedResources.TabBorderColor) {
+			this.border = new DynamicFillBox (HostResourceProvider, NamedResources.TabBorderColor) {
 				Frame = new CGRect (0, 0, 1, 1)
 			};
-			header.AddSubview (border);
+			header.AddSubview (this.border);
 
 			this.propertyFilter = new NSSearchField {
 				ControlSize = controlSize,
 				PlaceholderString = LocalizationResources.PropertyFilterLabel,
 				TranslatesAutoresizingMaskIntoConstraints = false,
 			};
-			((NSView)header.ContentView).AddSubview (this.propertyFilter);
+			((NSView)this.header.ContentView).AddSubview (this.propertyFilter);
 
 			this.propertyFilter.Changed += OnPropertyFilterChanged;
 
@@ -173,7 +172,7 @@ private void Initialize ()
 				EdgeInsets = new NSEdgeInsets (0, 0, 0, 0)
 			};
 
-			((NSView)header.ContentView).AddSubview (this.tabStack);
+			((NSView)this.header.ContentView).AddSubview (this.tabStack);
 
 			this.propertyTable = new FirstResponderOutlineView {
 				RefusesFirstResponder = true,
@@ -219,6 +218,17 @@ private void Initialize ()
 			ViewDidChangeEffectiveAppearance ();
 		}
 
+		private void UpdateResourceProvider()
+		{
+			if (this.propertyTable.Delegate != null)
+				this.propertyTable.Delegate = new PropertyTableDelegate (HostResourceProvider, this.dataSource);
+
+			this.header.HostResourceProvider = HostResourceProvider;
+			this.border.HostResourceProvider = HostResourceProvider;
+
+			ViewDidChangeEffectiveAppearance ();
+		}
+
 		private void OnPropertiesChanged (object sender, EventArgs e)
 		{
 			this.propertyTable.ReloadData ();