比较列表并使用LINQ返回公共对象

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication5
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Customer> custList = new List<Customer>();

            custList.Add(new Customer { Name = "P1" });
            custList.Add(new Customer { Name = "P2" });
            custList.Add(new Customer { Name = "P3" });
            custList.Add(new Customer { Name = "P4" });
            custList.Add(new Customer { Name = "P5" });

            List<Customer> vendorList = new List<Customer>();
            vendorList.Add(new Customer { Name = "P1" });
            vendorList.Add(new Customer { Name = "P2" });

            //var v = custList.SelectMany(


        }
    }

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

}

如何复制这两个列表并仅查找custList和vendorList中存在的那些客户？

Answer 1

理想的情况下,让你的Customer类重写GetHashCode和Equals(更重要的是,实施IEquatable<Customer>).然后你可以使用:

var customerVendors = custList.Intersect(vendorList);

否则,您将实现IEqualityComparer<T>比较客户的相等性(例如,通过名称,但您可以选择其他比较),然后使用:

var customerVendors = custList.Intersect(vendorList, new CustomerComparer());

请注意,这些都会返回IEnumerable<Customer>,这将被懒惰地评估.有时这就是你想要的,但如果你真的需要一个List<Customer>,最后只需要打电话ToList(),例如

var customerVendors = custList.Intersect(vendorList).ToList();

Answer 2

从评论到另一个答案:

Intersect期望两个列表具有相同的类型.如果它们的类型不同,如果两个列表中的属性名称不同,该怎么办？我如何在这里使用SelectMany

在这种情况下,您可能希望使用Join.如

var result = from item1 in list1
             join item2 in list2
             on item1.Foo equals item2.Bar
             select new { item1, item2 }; // select whatever you need in the resultset