c# - 用于导航对象层次结构的 LINQ 查询

Question

假设我有一个国家/州/城市的对象图，如下所示:

public class City
{
    public string Name { get; set; }
}

public class State
{
    public List<City> Cities { get; set; }
}

public class Country
{
    public List<State> States { get; set; }
}

有没有一种简单的方法来查询 List<Country>获取所有城市？

Answer 1

countryList.SelectMany(c => c.States).SelectMany(s => s.Cities) 怎么样？

或者可能是这个？

var cities = from country in countryList
             from state in country.States
             from city in state.Cities
             select city;