// 定时器
        static Timer statsTimer;
        static Timer emailTimer;

        // 定时间隔
        private long EmailInterval = ForumConfiguration.GetConfig().ThreadIntervalEmail * 60000;
        private long StatsInterval = ForumConfiguration.GetConfig().ThreadIntervalStats * 60000;

        public String ModuleName { 
            get { return "ForumsHttpModule"; } 
        }    


        // *********************************************************************
        //  ForumsHttpModule
        //
        /// <summary>
        /// Initializes the HttpModule and performs the wireup of all application
        /// events.
        /// </summary>
        /// <param name="application">Application the module is being run for</param>
        public void Init(HttpApplication application) { 

            // Wire-up application events
            //
            // 略去其他代码
            
            ForumConfiguration forumConfig = ForumConfiguration.GetConfig();

            // 如果使用定时器并且定时器还没初始化
            if( forumConfig != null
            &&  forumConfig.IsBackgroundThreadingDisabled == false ) {
                if (emailTimer == null)
                    // 新建定时器
                    // 新建一个TimerCallback委托，具体要执行的方法在ScheduledWorkCallbackEmailInterval中
                    emailTimer = new Timer(new TimerCallback(ScheduledWorkCallbackEmailInterval), application.Context, EmailInterval, EmailInterval);

                if( forumConfig.IsIndexingDisabled == false 
                &&    statsTimer == null ) {
                    statsTimer = new Timer(new TimerCallback(ScheduledWorkCallbackStatsInterval), application.Context, StatsInterval, StatsInterval);
            }
        }
        }

        /// <summary>
        /// 释放定时器
        /// </summary>
        public void Dispose() {
            statsTimer = null;
            emailTimer = null;
        }

        Timer Callbacks