如何使用linq按主键组合三个对象列表

Question

我正在尝试合并 3 个对象列表。我有一个人员列表、地址列表和一个 addressRelation 列表。 我想将这些列表组合成一个按 person.id 排序的新列表，将其用作列表视图的数据源，然后能够访问 aspx 页面中的属性。

这可能吗？

Answer 1

大概

using System.Linq;

class Person
{
    public int Id; 
    public string Name;
}

class Address
{
    public int Id;
    public string Street;
}

class PersonAddress
{
    public int PersonId, AddressId;
}

public class Program
{
    public static void Main(string[] args)
    {
        var personList = new []
        {
            new Person { Id = 1, Name = "Pete" },
            new Person { Id = 2, Name = "Mary" },
            new Person { Id = 3, Name = "Joe" }
        };

        var addressList = new []
        {
            new Address { Id = 100, Street = "Home Lane" },
            new Address { Id = 101, Street = "Church Way" },
            new Address { Id = 102, Street = "Sandy Blvd" }
        };

        var relations = new [] 
        {
            new PersonAddress { PersonId = 1, AddressId = 101 },
            new PersonAddress { PersonId = 3, AddressId = 101 },

            new PersonAddress { PersonId = 2, AddressId = 102 },
            new PersonAddress { PersonId = 2, AddressId = 100 }
        };

        var joined = 
                    from par in relations
                    join p in personList
                        on par.PersonId equals p.Id
                    join a in addressList
                        on par.AddressId equals a.Id
                    select new { Person = p, Address = a };

        foreach (var record in joined)
            System.Console.WriteLine("{0} lives on {1}", 
                                   record.Person.Name, 
                                   record.Address.Street);
    }
}

输出：

Pete lives on Church Way
Mary lives on Sandy Blvd
Mary lives on Home Lane
Joe lives on Church Way