ASP.NET中LINQ的基本用法

此Demo只是一个极其简单的LINQ查询Demo

一个类

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

namespace ConsoleApp1
{
   public class NBA_Star
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Champion { get; set; }

    }
}

主类的代码LINQ的代码

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

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var nba_stars = new List<NBA_Star> {
                new NBA_Star{ FirstName="迈克尔", LastName="乔丹", Champion=6},
                new NBA_Star{ FirstName="蒂姆", LastName="邓肯", Champion=5},
                new NBA_Star{ FirstName="勒布朗", LastName="詹姆斯", Champion=3},
                new NBA_Star{ FirstName="史蒂芬 ", LastName="库里", Champion=3},
                new NBA_Star{ FirstName="史蒂夫 ", LastName="纳什", Champion=0}
        };
            //查询语法查询出，至少得到5个总冠的球星

            var starts = from star in nba_stars
                         where star.Champion >= 5
                         select new
                         {
                             Name = star.FirstName + "." + star.LastName,
                             Champion = star.Champion
                         };
            Console.WriteLine("至少五个总冠军的球星");
            foreach (var item in starts)
            {
                Console.WriteLine($"姓名：{item.Name},总冠军:{item.Champion}");
            }
            Console.WriteLine();

            //查找至少得到5个总冠的球星的Lambda
            var starts2 = nba_stars.Where(s => s.Champion >= 5).Select(s => new
            {
                Name = s.FirstName + "." + s.LastName,
                Champion = s.Champion
            });

            foreach (var item in starts2)
            {
                Console.WriteLine($"姓名：{item.Name},总冠军:{item.Champion}");
            }
            Console.WriteLine();


            //五个总冠军的人数
            var starts3 = nba_stars.Where(s => s.Champion >= 5).Count();
            Console.WriteLine("至少得到5个总冠的球星人数"+starts3);
            Console.WriteLine();

            //最后一个冠军
            var last_star = nba_stars.LastOrDefault();
            Console.WriteLine("最后一个夺冠球星"+last_star.FirstName+"."+last_star.LastName);
            Console.WriteLine();



            //得到六冠的球星是
            var Six_Star = nba_stars.Select(ss => new
            {
                Name = ss.FirstName + "." + ss.LastName,
                Champion = ss.Champion
            }).FirstOrDefault(s => s.Champion == 6);
            Console.WriteLine($"得到6冠的球星是{Six_Star.Name}");
            Console.WriteLine();
        }
    }
}

也是为了方便以后用到找不到的时候，可以来自己博客查看