added missing logic

Catamaran/Catamaran/CollectionGenericObjects/ArrayGenericObjects.cs

@@ -37,9 +37,13 @@ namespace Catamaran.CollectionGenericObjects
         }
 
         public T? Get(int position)
+        {
+            if (position >= 0 && position < Count)
             {
                 return _collection[position];
             }
+            return null;
+        }
 
         public int Insert(T obj)
         {