Asp.net 2.0 提供了一个新的数据缓存功能,就是利用sql server2005 的异步通知功能来实现缓存
1.首先在sqlserver2005 中创建一个test的数据库.添加一个 employee的数据库表.
1
CREATE TABLE [dbo].[employee](
2 [id] [int] IDENTITY(1,1) NOT NULL,
3 [name] [varchar](50)
4)
5
CREATE TABLE [dbo].[employee](2
[id] [int] IDENTITY(1,1) NOT NULL,3
[name] [varchar](50) 4
) 5
2使用 vs2005 创建一个新的asp.net项目.
web.config如下
1<?xml version="1.0"?>
2<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
3 <appSettings/>
4 <connectionStrings>
5 <add name="mySource" connectionString="Data Source=.\sql2005;Initial Catalog=test;Persist Security Info=True;User ID=sa;Password=sasa" providerName="System.Data.SqlClient"></add>
6 </connectionStrings>
7 <system.web>
8 <compilation debug="true"/>
9 <authentication mode="Windows"/>
10 </system.web>
11</configuration>
12
<?xml version="1.0"?>2
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">3
<appSettings/>4
<connectionStrings>5
<add name="mySource" connectionString="Data Source=.\sql2005;Initial Catalog=test;Persist Security Info=True;User ID=sa;Password=sasa" providerName="System.Data.SqlClient"></add>6
</connectionStrings>7
<system.web>8
<compilation debug="true"/>9
<authentication mode="Windows"/>10
</system.web>11
</configuration>12
3.编写global.asax文件,启动监听sql2005通知事件.
<%@ Application Language="C#" %><%@ Import Namespace="System.Data.SqlClient" %><script runat="server"> void Application_Start(object sender, EventArgs e) 
{
string connStr=ConfigurationManager.ConnectionStrings["mySource"].ConnectionString; SqlDependency.Start(connStr);
} void Application_End(object sender, EventArgs e) { string connStr = ConfigurationManager.ConnectionStrings["mySource"].ConnectionString; SqlDependency.Stop(connStr); }</script>4.编写数据访问代码.创建一个EmployeeData的类,代码如下
using System;using System.Data;using System.Data.SqlClient;using System.Configuration;using System.Data.Common;using System.Web;using System.Web.Caching;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;/// <summary>/// EmployeeData 的摘要说明/// </summary>public class EmployeeData{ public EmployeeData()
{
} private HttpContext context; public DataSet GetCacheData() { context = HttpContext.Current; DataSet cache =(DataSet) context.Cache["employee"]; if (cache == null) { return GetData(); } else { return cache; } } public DataSet GetData() { string connStr = ConfigurationManager.ConnectionStrings["mySource"].ConnectionString; SqlConnection conn = new SqlConnection(connStr); SqlDataAdapter adp = new SqlDataAdapter("select id,name from dbo.employee", conn); SqlCacheDependency dep = new SqlCacheDependency(adp.SelectCommand); DataSet ds=new DataSet(); adp.Fill(ds); context.Cache.Add("employee", ds, dep, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.Default, new CacheItemRemovedCallback(this.DataDiff)); return ds; } public void DataDiff(string key, object value, CacheItemRemovedReason reason) { Console.WriteLine("key:" + key); GetData(); }}这里需要注意的是 select语句的写法, 不能使用 select * 的方式,一定要在表名前加架构名称 如我们这里的 dbo.employee.
5.编写测试页面代码.
<%@ 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>无标题页</title></head><body> <form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" runat="server" > </asp:GridView> </div> </form></body></html>6.插入后台代码
using System;using System.Data;using System.Configuration;using System.Web.Caching;using System.Data.SqlClient;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { EmployeeData em=new EmployeeData(); GridView1.DataSource = em.GetCacheData(); GridView1.DataBind(); }}