Linq學習筆記(1.1)——where

(我註：下文是一個linq關鍵字where的一些用法，原始碼裡面都有詳細的注釋說明，大家有興趣的話，可以試下在新建立的WebForm項目的Default.aspx.cs檔案裡面粘貼如下代碼，看看是不是出來結果的那個圖）

 

using System;<br />using System.Data;<br />using System.Configuration;<br />using System.Linq;<br />using System.Web;<br />using System.Web.Security;<br />using System.Web.UI;<br />using System.Text;<br />using System.Web.UI.WebControls;<br />using System.Web.UI.WebControls.WebParts;<br />using System.Web.UI.HtmlControls;<br />using System.Collections.Generic;<br />using System.Collections;</p><p>public partial class _Default : System.Web.UI.Page<br />{<br /> protected void Page_Load(object sender, EventArgs e)<br /> {<br /> //根據條件查詢數組#region 根據條件查詢數組<br /> Response.Write("<hr>列出數組中字元長度大於等於6的字串數組：<br>");<br /> string[] Demo1 = { "Ajax", "Csharp", "Javascript", "Css Desige", "Asp.net", "Gis" };<br /> var books = from n in Demo1<br /> where n.Length >= 6<br /> select n;</p><p> foreach (var book in books){<br /> Response.Write(string.Format("<span class='result'>{0}</span>", book));<br /> }</p><p> // where查詢的Lambda運算式#region where查詢的Lambda運算式<br /> Response.Write("<hr>where查詢的快捷方法：<br>");<br /> var books2 = Demo1.Where(book => book.Length >= 6);</p><p> foreach (var book in books2)<br /> {<br /> Response.Write(string.Format("<span class='result'>{0}</span>", book));<br /> }</p><p> //根據條件查詢集合體#region 根據條件查詢集合體</p><p> Response.Write("<hr>列出集合中語言為Chinese的學生：<br>");<br /> List<Student> Demo2 = GetStudents();<br /> var students1 = from n in Demo2<br /> where n.Language == "Chinese"<br /> select n.Name;</p><p> foreach (var student in students1){<br /> Response.Write(string.Format("<span class='result'>{0}</span>", student));<br /> }</p><p> //根據條件查詢集合體#region 根據條件查詢集合體<br /> Response.Write("<hr>列出集合中年齡大於等於20的英國或蘇格蘭學生：<br>");<br /> var students2 = from n in Demo2<br /> where (n.Language == "English" || n.Language == "Scotland") && n.Age >= 20<br /> select n;</p><p> foreach (var student in students2){<br /> Response.Write(string.Format("<span class='result'>{0}</span>", student.Name));<br /> } }</p><p> //構造一個學生集合體#region 構造一個學生集合體<br /> private List<Student> GetStudents()<br /> {<br /> List<Student> students = new List<Student> {<br /> new Student{ Name="YOUNG", Age=25, Language="Chinese"},<br /> new Student{ Name="JESSIE", Age=21, Language="Scotland"},<br /> new Student{ Name="KELLY", Age=18, Language="English"},<br /> new Student{ Name="JUNE", Age=20, Language="English"},<br /> new Student{ Name="ADRIAN", Age=22, Language="Italy"},<br /> new Student{ Name="BRUCE", Age=17, Language="Scotland"},<br /> new Student{ Name="BRANT", Age=30, Language="Germany"},<br /> new Student{ Name="BEN", Age=25, Language="Chinese"}<br /> };<br /> return students;<br /> }<br />}</p><p>//學生類#region 學生類<br />class Student<br />{<br /> public int Age { get; set; }<br /> public string Name { get; set; }<br /> public string Language { get; set; }<br />}

 

顯示結果：

 

 

轉自：http://www.cnblogs.com/young18/archive/2007/06/05/772127.html