在一个列表中查找不在另外一个列表中的元素,该怎么处理

在一个列表中查找不在另外一个列表中的元素

C# code

rptProdct2.DataSource = (from p in plist                    join s in shopcart on p.ProductID equals s.ID                     where p.ProductID != s.ID                     orderby p.NowPrice descending                     select p).OrderBy(p => p.NowPrice).Take(10);rptProdct2.DataBind();

C# code

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{    public class ShopCart    {        public int ID { get; set; }        public int Count { get; set; }    }    public class Product    {        public int ProductId { get; set; }        public decimal Price { get; set; }        public string ProductName { get; set; }        public override string ToString()        {            return ProductName;        }    }    class Program    {        static void Main(string[] args)        {            List<Product> productList = new List<Product>()            {                new Product(){ ProductId=1, Price=10, ProductName="商品1"},                new Product(){ ProductId=2, Price=10, ProductName="商品2"},                new Product(){ ProductId=3, Price=10, ProductName="商品3"},                new Product(){ ProductId=4, Price=10, ProductName="商品4"}            };            List<ShopCart> shopCart = new List<ShopCart>()             {                new ShopCart(){ ID=1, Count=10},                new ShopCart(){ ID=2, Count=10}            };            var query = productList.Except(from x in shopCart select productList.Where(y => y.ProductId == x.ID).Single());            query.ToList().ForEach(x => Console.WriteLine(x));        }    }}