LINQ简单案例

1.在visual studio 创建一个解决方案，新建一个控制台程序Kong

2.新建两个类，分别为Master 类和Kongfu类  Master类中包含成员如下，并重写ToString方法

 namespace linQ
 {
     class Master
     {
         public int id;
         public string name;//什么人
         public string kongfu;//什么功夫
         public int level;//武学等级

         public override string ToString()
         {
             return "序号" + id +"  "+ "名字" + name +"  " +"功夫" + kongfu +"   " +"武学等级" + level;
         }
     }
 }
Kongfu类

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

 namespace linQ
 {
     class Kongfu
     {
         public int id;//武学ID
         public string name;//武学名称
         public int power;//伤害

         public override string ToString()
         {
             return "ID为" + id + "名字" + name + "伤害" + power;
         }
     }
 }

Main方法中进行查询

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

 namespace linQ
 {
     class Program
     {
         static void Main(string[] args)
         {
             //创建一个LIST列表，并插入数据
             List<Master> master=new List<Master>()
             {
                 new Master(){id=,kongfu="葵花宝典",level =,name = "东方不败"},
                 new Master(){id=,kongfu="独孤九剑",level = ,name ="令狐冲"},
                 new Master(){id=,kongfu ="辟邪剑谱",level = ,name="林平之"},
                 new Master(){id=,kongfu="葵花宝典",level =,name="岳不群"}

                };
             List<Kongfu> kongfu=new List<Kongfu>()
             {
                 new Kongfu(){id=,name ="葵花宝典",power =},
                 new Kongfu(){id=,name = "独孤九剑",power = },
                 new Kongfu(){id=,name = "辟邪剑谱",power = }

             };
             //LINQ方法查询数据
             /*var res = from m in master
                 where m.level > 8//查询武学等级大于8的人的相关数据
                 select m;*/
             //如果查询两个表相关的数据
           //  var res = from master1 in master
              //   from kongfu1 in kongfu
                 //查询等级大于4并且上大于武学伤害大于200的相关数据
                // where master1.level > 4 && kongfu1.power > 200
                 //select new {a=master1,b=kongfu1};
                 //select master1.name;//只输出修炼人的名称

             //如果要对结果根据等级进行排序,查询修炼葵花宝典的人，并进行等级排序
             /*var res1 = from m in master
                 from n in kongfu
                 where m.kongfu == "葵花宝典"
                 orderby m.level
                 select m;*/
             //如果用Join on方法进行连接,根据两个类中的武学进行连接
             var res2 = from m in master
                 join n in kongfu on m.kongfu equals n.name
                 where m.level >
                 select m.name;

             //用循环遍历输出显示想要查询的结果
             foreach (var a in res2)
             {
                 Console.WriteLine(a);
             }
             Console.ReadKey();
         }
     }
 }