C#LINQ查询表达式用法
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代码如下,谢谢阅读,控制台应用程序:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml.Linq;
namespace LinqQueryDemo
{
class Student
{
public string Name { get; set; }
public bool Sex { get; set; }
public int Age { get; set; }
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("===============数组的Linq查询=============");
//隐式类型化数组
var persons = new[]{
new {Name="王二" ,Sex=true,Age=17},
new {Name="张三", Sex=true,Age=15},
new {Name="李四", Sex=true,Age=21}
};
/*
* 执行简单Linq查询
* 检索所有年龄在25岁以内的人
* 查询结果放在results变量中
* results变量的类型与数组persons相同
*/
var results = from p in persons
where p.Age <= 25
select p;
foreach (var person in results)
{
Console.WriteLine(person.Name);
}
Console.WriteLine("===============集合的Linq查询=============");
//集合构造者new List<Student>(){ }
//对象构造者new Student(){ }
List<Student> students = new List<Student>(){ new Student(){ Name="张三", Sex=true, Age=25},
new Student(){ Name="李文平", Sex=true, Age=22},
new Student(){ Name="刘庆溪", Sex=true, Age=22}
};
var stus = from p in students
where p.Age <= 25
select p;
foreach (var stu in stus)
{
Console.WriteLine(stu.Name);
}
/* 执行简单Linq查询XML
* 检索所有年龄在25岁以内的学生信息
* 查询结果放在stuResults变量中
*/
Console.WriteLine("===============XML的Linq查询=============");
string xml = "<students><student><Name>王二</Name><Sex>true</Sex><Age>28</Age></student><student><Name>李四</Name><Sex>true</Sex><Age>22</Age></student><student><Name>张三</Name><Sex>true</Sex><Age>25</Age></student></students>";
using (StringReader reader = new StringReader(xml))//创建字符串读取器
{
XDocument xDoc = XDocument.Load(reader);//装载xml
var stuResults = from p in xDoc.Element("students").Elements("student")
where Convert.ToInt32(p.Element("Age").Value) <= 25
select p;
foreach (var stu in stuResults)
{
Console.WriteLine(stu.Element("Name").Value);
}
}
}
}
}
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谢谢阅读,有错请指出,不甚感激。
posted on 2012-09-25 17:21 程序猴chengxuhou.com 阅读(4034) 评论(0) 编辑 收藏 举报