public class ManagePage:System.Web.UI.Page
    {
        public ManagePage()
        {
            this.Load+=new EventHandler(ManagePage_Load);
        }

        public void ManagePage_Load(object sender, EventArgs e)
        {
            //如果Session为Null
            if (Session["AdminName"] == null)
            {
                Response.Write(" <script type='text/javascript'>parent.location.href='login.aspx'</script>");
                Response.End();
            }
        }
    }

------解决方案--------------------
具体怎么验证的实现方式很多，但是必须保证每次请求都要通过验证