几种判断asp.net中session过期方法的比较_.Net教程

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
if (Session["username"] != null)
{

//登陆成功的情况
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "", "<script>alert('登录成功！')</script>");
}
else
{
//过期，重新登录
Response.Redirect("LoginForm.aspx");

}
}
}

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace JudgeSessionOutTime
{
//1.继承IHttpModule类，实现接口成员
public class Module:IHttpModule
{
#region IHttpModule 成员

public void Dispose()
{
throw new NotImplementedException();
}

//2.在Init()方法中对Context进行注册AcquireRequestState事件。
public void Init(HttpApplication context)
{
context.AcquireRequestState+=new EventHandler(context_AcquireRequestState);
}

//3.完善AcquireRequestState方法，然后判断session过期
public void context_AcquireRequestState(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;

if (app.Context.Session["username"] == null)
{
app.Response.Write("<script>alert('session到期！');</script>");
}
}

#endregion
}
}

<httpModules>

<!--重写IHttpModule类，需要配置的信息-->
<add name="demo" type="JudgeSessionOutTime.Module"/>
<!--type后面是命名空间.类名-->

</httpModules>

//JudgeSession 类

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace JudgeSessionOutTime
{
public class JudgeSession : System.Web.UI.Page
{
protected override void OnInit(EventArgs e)
{
if (Session["username"] == null)
{
Response.Write("session过期!");
}
else
{
Response.Write("session没有过期，用户名："+Session["username"].ToString());
}
}

}
}