一级目录

1. LINQ表达式
2. 反射type
3. 特性

LINQ表达式

using System;using System.Collections.Generic;using System.Collections;using System.Linq;public class Student{public  string  Name { set; get; }public int Age { set; get; }public string GongFu { set; get; }public override string ToString(){// return $\"name:{ Name},Age:{Age},GongFu:{ GongFu}\";return string.Format(\"name:{0},Age:{1},GongFu:{2}\", Name, Age, GongFu);}}public class GongFu{public string Name { set; get; }public int ShangHai { set; get; }public override string ToString(){return string.Format(\"name:{0},ShangHai:{1}\", Name,ShangHai);}}namespace 武学功夫{class Program{static void Main(string[] args){List<Student> str = new List<Student>{new Student{Name=\"小明\",Age=18,GongFu=\"葵花宝典\" },new Student{Name=\"小红\",Age=28,GongFu=\"祥龙十八掌\" },new Student{Name=\"小a\",Age=18,GongFu=\"祥龙十八掌\" },new Student{Name=\"小b\",Age=8,GongFu=\"祥龙十八掌\" },new Student{Name=\"小c\",Age=48,GongFu=\"祥龙十八掌\" },new Student{Name=\"老王\",Age=113,GongFu=\"六脉神剑\" },new Student{Name=\"张三\",Age=13,GongFu=\"葵花点穴手\" },new Student{Name=\"李四\",Age=11,GongFu=\"金刚不坏\" },};List<GongFu> fu = new List<GongFu>{new GongFu{Name=\"葵花宝典\",ShangHai=86 },new GongFu{Name=\"祥龙十八掌\",ShangHai=70 },new GongFu{Name=\"六脉神剑\",ShangHai=99 },new GongFu{Name=\"葵花点穴手\", ShangHai=46},new GongFu{Name=\"金刚不坏\", ShangHai=66},};//1.查询//var str1 = from m in str//           from k in fu//        where m.GongFu==k.Name&&k.ShangHai>70//           select new { str=m,fu=k};//var str1= str.Where(sdsd =>  sdsd.Age > 50);// var str1=  str.SelectMany(m => fu, (m, k) => new { str = m, fu = k }).Where(x=>x.fu.Name==x.str.GongFu&&x.str.Age>100);//查找//2.排序//var str1 = from m in str//           where m.Age >5//          // orderby m.Age,m.Name//多个字段进行排序，先按照年龄，后按照名字//           orderby m.Age descending//从大到小进行排序//           select m;// var str1 = str.Where(m => m.Age > 50).OrderBy(m => m.Age).ThenBy(m => m.Name);//倒序OrderByDescending//3.联合查询//var str1 = from m in str//           join n in fu on m.GongFu equals n.Name//           select new { str = m, fu = n };////4.对结果进行分组查询//var str1 = from n in fu//           join m in str on n.Name equals m.GongFu//           into groups//           orderby groups.Count()//           select new { fu = n, count = groups.Count() };//按照自身字段进行分组groupvar str1 = from m in strgroup m by m.GongFu into gselect new { count = g.Count() ,key=g.Key};//g.Key表示按照哪个属性进行分的组//5.量词操作符//判断是否存在祥龙十八掌bool a= str.Any(m => m.GongFu== \"祥龙十八掌\");Console.WriteLine(a);//判断是否全部都是祥龙十八掌bool b =str.All(m => m.GongFu == \"祥龙十八掌\");Console.WriteLine(b);foreach (var item in str1){Console.WriteLine(item);}Console.ReadKey();}}}

反射type

using System;using System.Collections.Generic;using System.Linq;using System.Reflection;using System.Text;using System.Threading.Tasks;namespace 反射和特性type{class Program{static void Main(string[] args) {////每一个类对应一个type对象，这个type对象存储了这个类 有哪些方法跟哪些数据 哪些成员//    Myclass my = new Myclass();//    Type type = my.GetType();//通过对象来获取这个对象所在类的Type对象//    Console.WriteLine(type.Name);//获取类的名字//    Console.WriteLine(type.Namespace);//获取所在的命名空间//    Console.WriteLine(type.Assembly);//    FieldInfo[] array=  type.GetFields();//只能获取pubilc字段//    Console.WriteLine(\"-----------下面为类的字段-----------\");//    foreach(FieldInfo info in array)//    {//        Console.WriteLine(info + \"  \");//    }//    PropertyInfo[] infos = type.GetProperties();//    Console.WriteLine(\"-----------下面为类的属性-----------\");//    foreach (PropertyInfo info in infos)//    {//        Console.WriteLine(info + \"  \");//    }//    MethodInfo[] infos1 = type.GetMethods();//    Console.WriteLine(\"-----------下面为类的方法-----------\");//    foreach (MethodInfo info in infos1)//    {//        Console.WriteLine(info + \"  \");//    }//通过type对象可以获取它对应的类的所有成员(pubilc)Myclass my = new Myclass();Assembly assem = my.GetType().Assembly;//通过类的type对象获取它所在的程序集Assembly//还可以根据程序集的名字加载程序集//Assembly assembly1 = Assembly.Load(\"SomeAssembly\");//根据路径也可以// Assembly assembly2 = Assembly.LoadFile(@\"c:\\d\\d\\\");Console.WriteLine(assem.FullName);Type[] types=  assem.GetTypes();foreach(Type ty in types){Console.WriteLine(ty);}Console.ReadKey();}}}

特性

#define Istext  //定义一个宏using System;using System.Collections.Generic;using System.Diagnostics;using System.Linq;using System.Runtime.CompilerServices;using System.Text;using System.Threading.Tasks;特性{//1.特性类的后缀以Attribute结尾//2.需要继承自System.Attribute//3.一般情况下声明为sealed//4.一般情况下 特性类用来表示目标结构的一些状态（定义字段或者属性，一般不定义方法)[AttributeUsage(AttributeTargets.Class)]//表示该特性类可以应用到的程序结构有哪些sealed class MytextAttribute : System.Attribute{public string A { set; get; }public int Id { set; get; }public MytextAttribute(string str){this.A = str;}}}namespace 特性{    //通过特定属性的名字，给属性赋值，这种是命名参数[Mytext(\"简单的特性类\",Id =50)]//当我们使用特性的时候,后面的Attribute不用写class Program{//[Obsolete(\"这个方法过时了，使用NewMethod代替\")]//表示一个方法被弃用了,但是仍然可以用[Obsolete(\"dd\",true)]//这个这个方法就不能被调用了static void OldMethod(){Console.WriteLine(\"OldMethod\");}static void NewMethod(){Console.WriteLine(\"NewMethod\");}[Conditional(\"Istext\")]//若程序开头没有定义Istext的宏，则不会调用text1static void text1(){Console.WriteLine(\"text1\");}static void text2(){Console.WriteLine(\"text2\");}[DebuggerStepThrough]//可以跳过debugger的单步调试 不让进入该方法(当我们确定这个方法没有任何错误的时候，可以用这个)static void PrintOut(string str,[CallerFilePath]string filename=\" \",[CallerLineNumber] int linenumber=0,[CallerMemberName] string mathodName=\"\"){Console.WriteLine(str);Console.WriteLine(filename);//路径Console.WriteLine(linenumber);//运行行Console.WriteLine(mathodName);}static void Main(string[] args) {////    text1();//    text2();//    text1();//PrintOut(\"小明\");Type type = typeof(Program);//通过typeof+类名特可以获取type对象object[] array= type.GetCustomAttributes(false);MytextAttribute mytext= array[0] as MytextAttribute;Console.WriteLine(mytext.A);Console.WriteLine(mytext.Id);Console.ReadKey();}}