Linq 与 Lambda 简单使用

//Lambda表达式详解
//int
//List<int> numbers = new List<int> {1,2,3,4,5,6,7,8,9 };
//var n = numbers.Where(a => (a > 3));
//int [] ns = n.ToArray();//返回一个原对象的数组

//string
//List<string> strs = new List<string> {"1","2","3"};
//var s = strs.Where(a => (Convert.ToInt16(a)>2));
//string[] ss = s.ToArray();

//object
//List<People> strs = new List<People> { new People("evan", 20), new People("evanpei", 25)};
//var s = strs.Where(a => (a.age > 20));
//People[] ss = s.ToArray();

//Linq 列转换为集合
//DataTable dt = DBHelper.GetDataTable("SELECT b.ID,a.MODEL_NAME,b.PLAN_NAME FROM dbo.t_Model AS a LEFT JOIN dbo.t_TestPlan AS b ON b.ID = a.TESTPLAN_ID", 0, null);
//List<string> Modes = new List<string>();//所有方案 去重复
//var list = dt.AsEnumerable().Distinct().Select(t => t.Field<string>("PLAN_NAME")).ToList();
//Modes = list;

　　

C#3.0 LINQ 查询语法
首先来看一个很简单的LINQ查询例子，查询一个int数组中小于5的数字，并按照大小顺序排列：
static void Main(string[] args)
{
int[] arr = new int[] { 8, 5, 89, 41, 1, 2, 3, 65, 1 };
var m = from n in arr where n < 5 orderby n descending select n;//小于5，并且倒序排列显示
foreach (var n in m)
{
Console.WriteLine(n);
}
Console.ReadLine();
}