/// <summary> /// Find a tasklist by ID and then return its index /// </summary> /// <param name="observableCollection"></param> /// <param name="taskList"></param> /// <returns></returns> private int IndexOf(ObservableCollection<TaskList> lists, TaskList taskList) { try { TaskList taskListRef = lists.Single(tl => tl.ID == taskList.ID); return lists.IndexOf(taskListRef); } catch (Exception) { return -1; } }