C#3.0新特性

对象初始化器

扩展方法

集合初始化器

匿名类型

linq

Lamda表达式

 

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{ class Program { static void Main(string[] args) { Person person = new Person() { ID = 1, Name = "xuxu" }; person.SayHello(); Console.ReadKey(); } } public class Person { public int ID { get; set; } public string Name { get; set; } } public static class ExtentPerson { public static void SayHello(this Person p){ Console.Write("ID:{0}, Name:{1}",p.ID,p.Name); } }}

 

 

匿名类型

var data = new {username = "zhuye",age = 26};Console.WriteLine("username:{0} age:{1}", data.username, data.age);

集合初始化器

var persons = new List<Person> { new Person {username = "a", age=1}, new Person {username = "b", age=2}};

Lamda表达式

(参数列表) => 表达式或者语句块

其中：

参数个数：可以有多个参数，一个参数，或者无参数。

表达式或者语句块：这部分就是我们平常写函数的实现部分（函数体）。

var list = new [] { "aa", "bb", "ac" };var result = Array.FindAll(list, s => (s.IndexOf("a") > -1));foreach (var v in result) Console.WriteLine(v);

复杂一点的例子

public delegate int mydg(int a, int b); public static class LambdaTest{ public static int oper(this int a, int b, mydg dg) { return dg(a, b); }}Console.WriteLine(1.oper(2, (a, b) => a + b));Console.WriteLine(2.oper(1, (a, b) => a - b));

查询句法

var persons = new List<Person> { new Person {username = "a", age=19}, new Person {username = "b", age=20}, new Person {username = "a", age=21},};var selectperson = from p in persons where p.age >= 20 select p.username.ToUpper();foreach(var p in selectperson) Console.WriteLine(p);