清除所有Cookie

        /**//// <summary>
        /// 清除所有Cookie
        /// </summary>
        public static void ClearCookies()
        {
            int c = HttpContext.Current.Request.Cookies.Count;

            for(int i = 0; i < c; i ++)
            {
                HttpCookie hc = HttpContext.Current.Request.Cookies[i];
                hc.Expires = DateTime.Now.AddDays(-1);
                HttpContext.Current.Response.Cookies.Add(hc);
            }
        }