public string GetSysConfigByKey(string key)        {            if (object.Equals(HttpContext.Current.Cache["Cache_SysConfig"], null))            {                this.LoadSysConfigToCache();            }            Hashtable hashtable = (Hashtable)HttpContext.Current.Cache["Cache_SysConfig"];            if (hashtable.ContainsKey(key))            {                return hashtable[key].ToString();            }            return "";        }

　　写入缓存

public void LoadSysConfigToCache()        {            try            {                if (object.Equals(HttpContext.Current.Cache["Cache_SysConfig"], null))                {                    DataTable allSysConfig = new SysConfigBLL().GetAllSysConfig();                    Hashtable hashtable = new Hashtable();                    foreach (DataRow row in allSysConfig.Rows)                    {                        hashtable.Add(row["ConfigKey"].ToString(), row["ConfigValue"].ToString());                    }                    HttpContext.Current.Cache.Insert("Cache_SysConfig", hashtable);                }            }            catch (Exception exception)            {                ExceptionLogFactory.CreateObject(enuExceptionType.File, exception);                throw;            }        }