Linq联合查询

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主程序

class Program    {        private static void Main(string[] args)        {            var masterList = new List<MartialArtsMaster>()            {                new MartialArtsMaster() {Id = 1, Name = "黄蓉", Age = 18, Menpai = "丐帮", Kongfu = "打狗棒法", Level = 9},                new MartialArtsMaster() {Id = 2, Name = "洪七公", Age = 70, Menpai = "丐帮", Kongfu = "打狗棒法", Level = 10},                new MartialArtsMaster() {Id = 3, Name = "郭靖", Age = 22, Menpai = "丐帮", Kongfu = "降龙十八掌", Level = 10},                new MartialArtsMaster() {Id = 4, Name = "任我行", Age = 50, Menpai = "明教", Kongfu = "葵花宝典", Level = 1},                new MartialArtsMaster() {Id = 5, Name = "东方不败", Age = 35, Menpai = "明教", Kongfu = "葵花宝典", Level = 10},                new MartialArtsMaster() {Id = 6, Name = "林平之", Age = 23, Menpai = "华山", Kongfu = "葵花宝典", Level = 7},                new MartialArtsMaster() {Id = 7, Name = "岳不群", Age = 50, Menpai = "华山", Kongfu = "葵花宝典", Level = 8},                new MartialArtsMaster() {Id = 8, Name = "令狐冲", Age = 23, Menpai = "华山", Kongfu = "独孤九剑", Level = 10},                new MartialArtsMaster() {Id = 9, Name = "梅超风", Age = 23, Menpai = "桃花岛", Kongfu = "九阴真经", Level = 8},                new MartialArtsMaster() {Id = 10, Name = "黄药师", Age = 23, Menpai = "梅花岛", Kongfu = "弹指神通", Level = 10},                new MartialArtsMaster() {Id = 11, Name = "风清扬", Age = 23, Menpai = "华山", Kongfu = "独孤九剑", Level = 10}            };            var kongfuList = new List<Kongfu>()            {                new Kongfu() {Id = 1, Name = "打狗棒法", Power = 90},                new Kongfu() {Id = 2, Name = "降龙十八掌", Power = 95},                new Kongfu() {Id = 3, Name = "葵花宝典", Power = 100},                new Kongfu() {Id = 4, Name = "独孤九剑", Power = 100},                new Kongfu() {Id = 5, Name = "九阴真经", Power = 100},                new Kongfu() {Id = 6, Name = "弹指神通", Power = 100}            };            //1,使用LINQ做查询( 表达式写法)            var res = from m in masterList//from后面设置查询的集合                      where m.Level > 8 && m.Menpai=="丐帮" //where后面跟上查询的条件                      select m;//表示m的结果结合返回           // 2,扩展方法的写法            var res1 = masterList.Where(Test1);            var res2 = masterList.Where(m => m.Level > 8 && m.Menpai=="丐帮" );            //3,LINQ 联合查询                       var res3 = from m in masterList                      from k in kongfuList                      where m.Kongfu == k.Name && k.Power > 90                      //select new {master = m, kongfu = k};                      select m;//取得所学功夫的杀伤力大于90 的武林高手            //扩展方法用法            var res6 =masterList.SelectMany(m => kongfuList, (m, k) => new { master = m, kongfu = k }).Where(x => x.master.Kongfu == x.kongfu.Name && x.kongfu.Power > 90);                  }        //过滤方法        static bool Test1(MartialArtsMaster master)        {            if (master.Level > 8) return true;            return false;        }    }

 class MartialArtsMaster    {        public int Id { get; set; }        public string Name { get; set; }        public int Age { get; set; }        public string Menpai { get; set; }        public string Kongfu { get; set; }        public int Level { get; set; }        public override string ToString()        {            return string.Format("Id: {0}, Name: {1}, Age: {2}, Menpai: {3}, Kongfu: {4}, Level: {5}", Id, Name, Age, Menpai, Kongfu, Level);        }    }

class Kongfu     {        public int Id { get; set; }        public string Name { get; set; }        public int Power { get; set; }        public override string ToString()        {            return string.Format("Id: {0}, Name: {1}, Power: {2}", Id, Name, Power);        }    }

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