cache应用（asp.net 2.0 SQL数据缓存依赖 [SqlCacheDependency ] ）

最新推荐文章于 2024-08-14 16:17:48 发布

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本文详细介绍了如何在ASP.NET 2.0中利用SQL Server 2005的异步通知功能实现数据缓存，包括数据库设置、代码实现及测试页面的编写。

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.

cache应用（asp.net 2.0 SQL数据缓存依赖 [SqlCacheDependency ] ） - qiuguangchun - sandea的个人主页

CREATE TABLE [dbo].[employee](
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[id] [int] IDENTITY(1,1) NOT NULL,
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[name] [varchar](50)
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)
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2使用 vs2005 创建一个新的asp.net项目.

web.config如下

<?xml version="1.0"?>
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<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
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<appSettings/>
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<connectionStrings>
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<add name="mySource" connectionString="Data Source=.\sql2005;Initial Catalog=test;Persist Security Info=True;User ID=sa;Password=sasa" providerName="System.Data.SqlClient"></add>
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</connectionStrings>
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<system.web>
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<compilation debug="true"/>
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<authentication mode="Windows"/>
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</system.web>
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</configuration>
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3.编写global.asax文件,启动监听sql2005通知事件.

<%@ Application Language="C#" %>

<%@ Import Namespace="System.Data.SqlClient" %>

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">

</head>

<body>

<div>

<asp:GridView ID="GridView1" runat="server" >

</asp:GridView>

</div>

</form>

</body>

</html>

6.插入后台代码