ASP.NET自定义输出缓存提供程序(2)

                foreach (var discarded in discardedList)

                {

                    Remove(discarded.Key);

                    DateTime discardedDate;

                    cacheExpireList.TryRemove(discarded.Key,

out discardedDate);

                }

            };

            timer.Start();

        }

        /// <summary>

        /// 添加缓存

        /// </summary>

        /// <param name="key">缓存的键</param>

        /// <param name="entry">缓存的对象</param>

        /// <param name="utcExpiry">过期时间</param>

        /// <returns>返回缓存值</returns>

        public override object Add(string key, object entry,

 DateTime utcExpiry)

        {

            FileStream fs = new FileStream(

String.Format("{0}{1}.binary", cachePath, key),

 FileMode.Create, FileAccess.Write);

            BinaryFormatter formatter = new BinaryFormatter();

            formatter.Serialize(fs, entry);

            fs.Close();

            cacheExpireList.TryAdd(key, utcExpiry.ToLocalTime());

            return entry;

        }

        /// <summary>

        /// 获得缓存值

        /// </summary>

        /// <param name="key">缓存键</param>

        /// <returns>缓存值</returns>