检查session判断用户是否退出登录

    protected void Page_Load(object sender, EventArgs e)
    {
        if (Session["UserID"] == null)
        {
            Page.RegisterStartupScript("Edit", "<script>alert('由于你长时间没有操作该页,系统超时,已自动注销！请重新登录！');window.location.href='http://www.cnblogs.com/Default.aspx';</script>");
            //Page.ClientScript.RegisterClientScriptBlock(typeof(string), "my", "<script>alert('由于你长时间没有操作该页,系统超时,已自动注销！请重新登录！');window.location.href='../Default.aspx'</script>", true); 

        }
    }
    protected void lnkBtnExit_Click(object sender, EventArgs e)
    {
        Session.Clear();
        Response.Redirect("http://www.cnblogs.com/Default.aspx");
    }