private void remove(NotificationItemViewModel vm)
 {
     if (_notificationItemList.Contains(vm))
     {
         _removedList.Add(vm.EmbeddedModel.ID);
         _notificationItemList.Remove(vm);
     }
     HasNotification = _notificationItemList.Count > 0;
 }
 public int IntexOf(NotificationItemViewModel vm)
 {
     lock (_notificationItemList)
         return(_notificationItemList.IndexOf(vm));
 }
        //public void Clear()
        //{
        //    lock (_notificationItemList)
        //        _notificationItemList.Clear();
        //}

        public void Remove(NotificationItemViewModel vm)
        {
            lock (_notificationItemList)
                remove(vm);
        }
 public void Add(NotificationItemViewModel vm)
 {
     lock (_notificationItemList)
         _notificationItemList.Add(vm);
 }