//Linq:language Intergarted Query 语言整合查询            //select * from tb_name            //条件必须实现IEnumerable接口            //Linq to SQL,Linq to Xml ,Linq to DataSet,Linq to Objects            int[] numbers = { 5, 10, 8, 3, 6, 12 };            //Query Systax            var numQuery1 = from num in numbers                            where num % 2 == 0                            orderby num                            select num;            foreach (int num in numQuery1)            {                Console.WriteLine(num);            }            //method Systax            var numQuery2 = numbers.Where(n => n % 2 == 0).OrderBy(n => n);            foreach (int num in numQuery2)            {                Console.WriteLine(num);            }            Console.ReadLine();

语法

private static void QuerySysnax()        {            //1.datasource            double[] numbers = { 110.00, 1, 2, 3, 4, 5, 6, 7 };            //2.query creation            var numquery = from num in numbers                           where num % 2 == 0                           select num;            int numCount = numquery.Count();            //3.query execution            Console.WriteLine("1234567890");            foreach (double num in numquery)            {                Console.WriteLine("{0,10}", num);            }        }

基本操作

from 获取数据源

where 过滤条件

order 排序

select 获取结果

group 

group into打包(group 一起用)

join 

let 中间变量

private static void myquery()        {            string[] mystrings = { "Hello qxw.", "This is Friday!", "Are you Happy?" };            var stringQuery = from s in mystrings                              let words = s.Split(' ')                              from word in words                              let w = word.ToUpper()                              select w;            //var stringQuery = from s in mystrings            //                  let w = s.ToUpper()            //                  select w;            foreach (var s in stringQuery)            {                Console.Write("{0} ", s);            }        }