/// <summary> /// Adds the specified item. /// </summary> /// <param name="item">The item.</param> /// <exception cref="RelationshipInstanceException"></exception> public void Add(TEntity item) { ///// // Input validation. ///// if (item == null) { return; } Precheck( ); if (_tracker.All(p => p.Key != item.Id)) { _tracker.Add((( IEntityInternal )item).MutableId); } }