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直接上代码:
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { /// <summary> /// 只作为快速的测试,没考虑编码规范的问题 /// </summary> class Program { static void Main(string[] args) { List<Student> student_List = new List<Student>(); for (int i = 0; i <= 3;i++ ) { Student studen = new Student(); studen.Age = i + 20; studen.Name = (i + 1).ToString(); student_List.Add(studen); } //查询,本人曾经出错的地方 //Student test = (Student)(from r in student_List where r.Age == 21 select r);//错误的写法,因为linq返回的是IEnumerable的 不能强制转换。 //正确的写法 var tmp = (from r in student_List where r.Age == 21 select r); Student test = tmp.FirstOrDefault();//或者这样写Student test = tmp.First(); //查询多条 List<Student> tmp_List = (from r in student_List where r.Age >= 20 select r).ToList(); } } class Student { public string Name { get; set; } public int Age { get; set; } } }
由于做项目过程中经常需要根据ID编号来查找某一项内容,使用Linq显得就比较方便。
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原文地址:http://www.cnblogs.com/dghwey/p/5090778.html