遭遇用户无法注销和清空Cookie,请大家帮忙看看

/// <summary>
        ///     退出登录
        /// </summary>
        public static void SignOut()
        {
            SignOut("/");
        }
        /// <summary>
        /// 退出登录
        /// </summary>
        /// <param name="gotourl">定向的URL</param>
        public static void SignOut(string gotourl)
        {
            if (HttpContext.Current.User != null && HttpContext.Current.User.Identity.IsAuthenticated)
            {
                //注销票据
                FormsAuthentication.SignOut();
            }
            else
            {
            }
            HttpContext.Current.Response.Redirect(gotourl);
            HttpContext.Current.Response.End();
        }

简直是能用的方法都用上了,为什么刷新页面用户还处于登陆状态,不解!!

登陆代码

        /// <summary>
        ///     登录
        /// </summary>
        /// <param name="username" type="string">
        ///     <para>
        ///         登录用户名
        ///     </para>
        /// </param>
        public static string SignIn(string username, string password)
        {
            bool isAuthenticated = IsAuthenticateds(username, password);
            string roles = string.Empty;
            if (isAuthenticated == true)
            {
                roles = UsersInRoless.GetUsersRolesString(username);
            }
            else
            {
                return "用户名或密码错误!";
            }
            DateTime expiration;
            expiration = DateTime.Now.AddMinutes(60);
            // 创建一个非永久性票
            FormsAuthenticationTicket authTicket = new
                 FormsAuthenticationTicket(1,                          // version
                                           username,           // user name
                                           DateTime.Now,               // creation
                                           expiration,// Expiration
                                           false,                      // Persistent
                                           roles);

            // 创建票的加密字符串表示形式，并将其作为数据存储在 HttpCookie 对象中
            string encryptedTicket = FormsAuthentication.Encrypt(authTicket);
            // Create a cookie and add the encrypted ticket to the
            // cookie as data.
            HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);
            authCookie.Domain = FormsAuthentication.FormsCookieName;
            ////删除旧的同名Cookie
            HttpContext.Current.Response.Cookies.Remove(authCookie.Domain);
            //将此 cookie 添加到返回给用户浏览器的 cookie 集合中。
            HttpContext.Current.Response.Cookies.Add(authCookie);
            HttpContext.Current.Response.Cookies[FormsAuthentication.FormsCookieName].Expires = authTicket.Expiration;

            //将用户重定向到最初请求的页。
            //HttpContext.Current.Response.Redirect(FormsAuthentication.GetRedirectUrl(username, false));
            return "";
        }

web.config
  <authentication mode="Forms">
   <forms name=".xxx.com" loginUrl="Login.aspx" protection="All" timeout="60" path="/"/>
  </authentication>
  <authorization>
   <allow users="*"/>
  </authorization> --------------------编程问答-------------------- Cookie.Expires=[DateTime];
Response.Cookies("UserName").Expires = 0 --------------------编程问答--------------------             HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.Expires = 0;
            HttpContext.Current.Response.AddHeader("pragma", "no-cache");
            HttpContext.Current.Response.AddHeader("cache-control", "private");
            HttpContext.Current.Response.CacheControl = "no-cache";
这样都试过了，还是不行

补充：.NET技术 ,  ASP.NET