c# - 使用 LINQ 获取一个 List<> 中的项目，这些项目位于另一个 List<> 中

Question

我认为有一个简单的 LINQ 查询可以做到这一点，我只是不确定如何。请参阅下面的代码片段，评论解释了我想做的事情:

class Program
{
  static void Main(string[] args)
  {
    List<Person> peopleList1 = new List<Person>();
    peopleList1.Add(new Person() { ID = 1 });
    peopleList1.Add(new Person() { ID = 2 });
    peopleList1.Add(new Person() { ID = 3 });
    peopleList1.Add(new Person() { ID = 4});
    peopleList1.Add(new Person() { ID = 5});

    List<Person> peopleList2 = new List<Person>();
    peopleList2.Add(new Person() { ID = 1 });
    peopleList2.Add(new Person() { ID = 4});


    //I would like to perform a LINQ query to give me only
    //those people in 'peopleList1' that are in 'peopleList2'
    //this example should give me two people (ID = 1& ID = 4)
  }
}


  class Person
  {
     public int ID { get; set; }
  }

Answer 1

var result = peopleList2.Where(p => peopleList1.Any(p2 => p2.ID == p.ID));