linq排序:Linq 学习(4) 投影、筛选和排序来源: 发布时间:星期五, 2009年1月9日 浏览:27次 评论:0
这里简单介绍Linq
![]() ![]() Select select 在 ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() select ![]() public 该扩展思路方法是在Enumerable类型中定义 ![]() ![]() // 数据源 ![]() ![]() var result = from student in DataSource.Students // 数据源类型筛选后 ![]() var result = from student in DataSource.Students // 新类型 var result = from student in DataSource.Students // 匿名类型 var result = from student in DataSource.Students // 对返回结果进行操作 var result = from student in DataSource.Students 由Select思路方法原型可看出 ![]() ![]() SelectMany SelectMany定义原型为: public 通过原型可以看出 ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() var result = DataSource.Students.SelectMany(str => str.Name); 等价 ![]() var result = from student in DataSource.Students 可以认为SelectMany是将序列 ![]() ![]() ![]() Distinct 原型为: public ![]() 去掉投影结果集 ![]() ![]() ![]() ![]() ![]() 上面同样 ![]() ![]() ![]() ![]() ![]() var result = DataSource.Students.SelectMany(str => str.Name).Distinct ![]() First、Last、Skip、Take、Single First 选择集和 ![]() ![]() ![]() var result = DataSource.Students.Select(student => student).First ![]() Last 选择集和 ![]() ![]() ![]() var result = DataSource.Students.Select(student => student).Last ![]() Skip 跳过N个元素 ![]() var result = DataSource.Students.Select(student => student).Skip(2).Count ![]() Take 选择集合 ![]() ![]() var result = DataSource.Students.Select(student => student).Skip(2).Take(1).Count ![]() Single 返回序列 ![]() ![]() ![]() ![]() ![]() var result = DataSource.Students.Select(student => student).Single ![]() // 结果: // Dark 下 ![]() ![]() 0
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