.net文件依赖缓存

.net的文件依赖缓存，是指缓存内容依赖于某个文件的变更状态，一旦这个文件变更了，缓存内容则被清除失效。

下面这个例子，一旦html文件被改变，就向httpruntime.cache中insert一个新的数组：Cache.Insert("TimeNow", timestr, dep);

myCacheDependency.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="myCacheDependency.aspx.cs" Inherits="myCacheDependency" %>

<!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>文件依赖缓存</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    </div>
    <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    </form>
</body>
</html>

myCacheDependency.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.Web.Caching;

public partial class myCacheDependency : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            Label1.Text = DateTime.Now.ToString();
        }

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string timestr = Convert.ToString(HttpRuntime.Cache["TimeNow"]);
        if (String.IsNullOrEmpty(timestr))
        { 
            //如果获取失败，重载当前时间
            timestr = DateTime.Now.ToString();

            //新建缓存依赖
            CacheDependency dep = new CacheDependency(Server.MapPath("./myPageCache.htm"),DateTime.Now);

            //插入缓存
            Cache.Insert("TimeNow", timestr, dep);
        }
        //显示时间
        Label1.Text = timestr;
    }
}

myPageCache.htm (内容略)