lambda表达式2
DataContext
DataContext类型（数据上下文）功能：
1.以日志形式记录DataContext生成的SQL
2.执行SQL（包括查询和更新语句）
3.创建和删除数据库
DataContext是实体和数据库之间的桥梁。
定义实体类
Customer.cs
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Data.Linq.Mapping;namespace DannyWeb{ [Table(Name="Customers")] public class Customer { [Column(IsPrimaryKey = true)] public string CustomerID { get; set; } [Column(Name = "ContactName")] public string Name { get; set; } [Column] public string City { get; set; } }}Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" runat="server"> </asp:GridView> </div> </form></body></html>
Default.aspx.cs
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data.Linq;using DannyWeb;public partial class _Default : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) { DataContext ctx = new DataContext("server=.;database=Northwind;uid=sa;pwd="); Table<Customer> Customers = ctx.GetTable<Customer>(); GridView1.DataSource = from c in Customers where c.CustomerID.StartsWith("A") select new { 顾客ID = c.CustomerID, 顾客名 = c.Name, 城市 = c.City }; GridView1.DataBind(); }}显示结果：
注意：
要手动添加System.Data.Linq.Mapping引用。
还可以直接使用如下：
using System.Data.SqlClient; ...IDbConnection conn = new SqlConnection("server=xxx;database=Northwind;uid=xxx;pwd=xxx");DataContext ctx = new DataContext(conn);...2011-6-2 11:27 danny