同步更新缓存中的数据集

发布时间：2020-12-12 16:03:27 所属栏目：MsSql教程来源：网络整理

导读：将一个取自SQL?Server的数据集放入缓存中了现在想数据库更新的时候缓存中的数据集同步更新? 第一步修改web,config !--定义数据库连接-- ?connectionStrings ??add?name="NorthwindConnectionString"?connectionString="Server=USERRYR/DB;Database=Northwin

将一个取自SQL?Server的数据集放入缓存中了现在想数据库更新的时候缓存中的数据集同步更新?

第一步

修改web,config


?<connectionStrings>
??<add?name="NorthwindConnectionString"?connectionString="Server=USERRYR/DB;Database=Northwind;UID=sa;pwd=密码"?providerName="System.Data.SqlClient"/>
?</connectionStrings>
?<system.web>
????
??<caching>
???<sqlCacheDependency?enabled="true"?pollTime="10000">
????<databases>
??????????
?????<add?connectionStringName="NorthwindConnectionString"?name="Categories"/>
????</databases>
???</sqlCacheDependency>
??</caching>
?</system.web>

第二步.定义cachedData测试类

using?System;
using?System.Data;
using?System.Configuration;
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;
using?System.Web.Caching;
using?System.Data.SqlClient;

///?<summary>
///?Summary?description?for?CachedData
///?</summary>
public?class?CachedData
{
????private?string?Key;
????private?string?_Source;
????///?<summary>
????///?指示数据从哪儿读取的
????///?</summary>
????public?string?Source?{?get?{?return?_Source;?}?}
?public?CachedData()
?{
????????Key?=?"Categories";
????????_Source?=?"未知";
?}

????//读取数据
????public?DataView?getFromCache()?{
????????if?(HttpRuntime.Cache[Key]?==?null)
????????{
????????????//取数据
????????????SqlConnection?conn?=?new?SqlConnection();
????????????conn.ConnectionString?=?ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
????????????SqlCommand?comm?=?new?SqlCommand("SELECT?[CategoryID],?[CategoryName],?[Description]?FROM?[Categories]",?conn);
????????????SqlDataAdapter?sda?=?new?SqlDataAdapter(comm);
????????????DataSet?ds?=?new?DataSet();
????????????conn.Open();
????????????sda.Fill(ds);
????????????DataView?dv?=?ds.Tables[0].DefaultView;
????????????conn.Close();

????????????//启用更改通知
????????????SqlCacheDependencyAdmin.EnableNotifications(ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);
????????????//连接到?SQL?Server?数据库并为?SqlCacheDependency?更改通知准备数据库表
????????????SqlCacheDependencyAdmin.EnableTableForNotifications(ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString,?"Categories");
????????????//制定缓存策略
????????????SqlCacheDependency?scd?=?new?SqlCacheDependency("Categories",?"Categories");
????????????//插入缓存
????????????HttpRuntime.Cache.Insert(Key,?dv,?scd);
????????????_Source?=?"Database";
????????????return?dv;
????????}
????????else?{
????????????//从缓存中取值
????????????_Source?=?"cache";
????????????return?(DataView)HttpRuntime.Cache[Key];
????????????
????????}
????}
}

3.测试页面

<%@?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>Untitled?Page</title>
</head>
<body>
????<form?id="form1"?runat="server">
????????<asp:Label?ID="Label1"?runat="server"?Text="Label"></asp:Label>
????????<asp:DataGrid?runat="server"?ID="Repeater1"></asp:DataGrid> 
????</form>
</body>
</html>
其对应cs文件 using?System; using?System.Data; using?System.Data.SqlClient; using?System.Configuration; 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) ????{ ???????? ????????????BindRepeater1(); ???????? ????} ????private?void?BindRepeater1(){ ????????CachedData?cd=new?CachedData(); ????????this.Repeater1.DataSource?=?cd.getFromCache(); ????????this.Repeater1.DataBind(); ????????this.Label1.Text?=?cd.Source; ????} }?? ?

（编辑：李大同）

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