added an instacedobject class

OmegaLeo.HelperLib/Models/InstancedObject.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace GameDevLibrary.Models
+{
+    public abstract class InstancedObject<T> where T : class
+    {
+        public static T Instance { get; private set; }
+
+        protected InstancedObject()
+        {
+            if (Instance != null)
+            {
+                throw new InvalidOperationException($"An instance of {typeof(T).Name} already exists.");
+            }
+
+            Instance = this as T;
+            if (Instance == null)
+            {
+                throw new InvalidOperationException($"Failed to cast {GetType().Name} to {typeof(T).Name}.");
+            }
+        }
+
+        ~InstancedObject()
+        {
+            if (Instance == this)
+            {
+                Instance = null;
+            }
+        }
+    }
+}