public class CacheContainer    {        private static Hashtable ht = new Hashtable();        /// <summary>        /// objId :缓存id，objObject：缓存对象,expires:绝对过期时间        /// </summary>        /// <param name="objId"></param>        /// <param name="objObject"></param>        /// <param name="expires"></param>        public void AddObject(string objId, object objObject, DateTime expires)        {            ContainerItem item = new ContainerItem() { Expires = expires, ObjObject = objObject };            ht[objId] = item;        }        /// <summary>        /// 默认缓存20分钟        /// </summary>        /// <param name="objId"></param>        /// <param name="objObject"></param>        public void AddObject(string objId, object objObject)        {            AddObject(objId, objObject, DateTime.Now.AddMinutes(20));        }        public object GetCacheObj(string objId)        {            object result = null;            if (ht.Contains(objId))            {                var item = (ContainerItem)ht[objId];                if (DateTime.Now<item.Expires)                {                    result =item.ObjObject;                }                else                {                    ht.Remove(objId);                }            }            return result;        }        /// <summary>        /// objId存在则删除，否则不处理        /// </summary>        /// <param name="objId"></param>        public void RemoveObject(string objId)        {            if (ht.Contains(objId))            {                ht.Remove(objId);            }        }    }    public class ContainerItem    {        public object ObjObject { get; set; }        public DateTime Expires { get; set; }    }