asp.net cookies 和session 双重验证 设定出错 。求解！！！

Question

设定  cookies 和session
      Session["blog_admin"] = username.Text.Trim();                        HttpCookie blog_name = new HttpCookie("blog_name", username.Text.ToString());                        HttpCookie blog_psd = new HttpCookie("blog_psd", psd);                        //设置 COOKIES的 过期 时间                        Response.Cookies["blog_name"].Expires = DateTime.Now.AddDays(1);
                        Response.Cookies["blog_psd"].Expires = DateTime.Now.AddDays(1);
                        Response.Cookies.Add(blog_name);                        Response.Cookies.Add(blog_psd);
                        Response.Redirect("user.aspx");                        ClientScript.RegisterStartupScript(this.GetType(), "alert", "<script>alert('登陆成功');</script>");
下次是  进入 页面 判断 是否登陆
  if (Request.Cookies["blog_name"] != null)
            {
                // 为什么 同时 验证 Session["blog_name"]。判断方便 。安全性强                SQLServer s = new SQLServer();                bool if_exist = s.selectuser(Request.Cookies["blog_name"].Value, Request.Cookies["blog_psd"].Value);                //判断用户名 和 密码 是否正确
                if (if_exist)
                {
                    //重新给 session[] 赋值                    if (Session["blog_admin"] == null)
                    {                        Session["blog_admin"] = Request.Cookies["blog_name"].ToString();                    }                    Response.Redirect("user.aspx");
                   // Server.Transfer();                }
                else
                {
                    //登陆导向                    Response.Write("<script>alert('用户名或者密码错误');window.parent.location.href='login.aspx';</script>");
             
                }            }
            else
            {                if (Session["blog_admin"]==null)
            {
                //登陆导向                Response.Write("<script>alert('你还没登录过');window.parent.location.href='login.aspx';</script>");
            }            }

Answer 1

  HttpCookie blog_name = new HttpCookie("blog_name", username.Text.ToString());  HttpCookie blog_psd = new HttpCookie("blog_psd", psd);  //设置 COOKIES的 过期 时间  blog_name.Expires = DateTime.Now.AddDays(1);
  blog_psd.Expires = DateTime.Now.AddDays(1);
  Response.Cookies.Add(blog_name);  Response.Cookies.Add(blog_psd);

Answer 2

啊  不是
Response.Cookies["blog_name"].Expires = DateTime.Now.AddDays(1);  Response.Cookies["blog_psd"].Expires = DateTime.Now.AddDays(1);
太感谢了 。