c# - 使用 LINQ 比较列表并返回常见对象

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; }
    }

}

我如何比较这两个列表并仅找到出现在 custList 和 vendorList 中的那些客户？

Answer 1

理想情况下，使您的 Customer类覆盖 GetHashCode和 Equals (更好的是，实现 IEquatable<Customer> )。然后你可以使用:

var customerVendors = custList.Intersect(vendorList);

否则，您将实现 IEqualityComparer<T>比较客户是否平等(例如按名称，但您可以选择其他比较)然后使用:

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

请注意，它们都将返回 IEnumerable<Customer> ，这将被延迟评估。有时这就是你想要的，但如果你真的需要 List<Customer> , 只需调用 ToList()在最后，例如

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