Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Game/Primitives/ObservableCollection.cs

@@ -0,0 +1,59 @@
+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace OpenRA.Primitives
+{
+	public class ObservableCollection<T> : Collection<T>, IObservableCollection
+	{
+		public event Action<IObservableCollection, object> OnAdd = (x, k) => { };
+
+		public event Action<IObservableCollection, object> OnRemove = (x, k) => { };
+		public event Action<IObservableCollection, int> OnRemoveAt = (x, i) => { };
+		public event Action<IObservableCollection, object, object> OnSet = (x, o, n) => { };
+		public event Action<IObservableCollection> OnRefresh = x => { };
+
+		public ObservableCollection() { }
+		public ObservableCollection(IList<T> list)
+			: base(list) { }
+
+		protected override void SetItem(int index, T item)
+		{
+			var old = this[index];
+			base.SetItem(index, item);
+			OnSet(this, old, item);
+		}
+
+		protected override void InsertItem(int index, T item)
+		{
+			base.InsertItem(index, item);
+			OnAdd(this, item);
+		}
+
+		protected override void ClearItems()
+		{
+			base.ClearItems();
+			OnRefresh(this);
+		}
+
+		protected override void RemoveItem(int index)
+		{
+			base.RemoveItem(index);
+			OnRemoveAt(this, index);
+		}
+
+		public IEnumerable ObservedItems => Items;
+	}
+}