Add project files.

ObservatoryCore/UI/TabTemplateSelector.cs

@@ -0,0 +1,31 @@
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using Avalonia.Metadata;
+using Observatory.UI.Views;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Observatory.UI
+{
+    public class TabTemplateSelector : IDataTemplate
+    {
+        public bool SupportsRecycling => false;
+
+        [Content]
+        public Dictionary<string, IDataTemplate> Templates { get; } = new Dictionary<string, IDataTemplate>();
+
+
+        public IControl Build(object param)
+        {
+            return new BasicUIView(); //Templates[param].Build(param);
+        }
+
+        public bool Match(object data)
+        {
+            return data is BasicUIView;
+        }
+    }
+}