c#怎么实现轮询算法 c#实现轮询算法实例代码

public class CountdownHelper   {      private const int CacheSlidingExpirationHour = 2;      private const string CountdownCurrentIndexCacheName = "OnlineMeetingCountdownCurrentIndex";      private static IAppLog log = AppLoggerManager.GetLogger(typeof(CountdownHelper));      private static Cache m_cache = HttpContext.Current.Cache;      private static object m_objCountdownCurrentIndexLock = new object();      private static int[] m_snIntervalSecond = new int[] { 0, 1 , 1 , 1}; //1显示 0不显示        public CountdownHelper()      {      }       public int GetCountdownAddedSecond()      {        lock (m_objCountdownCurrentIndexLock)        {          int nCountdownCurrentIndex = 0;            try          {            object objCountdownCurrentIndex = m_cache[CountdownCurrentIndexCacheName];            if (objCountdownCurrentIndex == null)            { //如果需要加缓存的，就用下面的 //m_cache.Insert(CountdownCurrentIndexCacheName, 1, null, Cache.NoAbsoluteExpiration, TimeSpan.FromHours(CacheSlidingExpirationHour), CacheItemPriority.NotRemovable, null); //不用加缓存的用下面的  m_cache.Insert(CountdownCurrentIndexCacheName, 1, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);            }            else            {              nCountdownCurrentIndex = (int)objCountdownCurrentIndex;               if (nCountdownCurrentIndex == m_snIntervalSecond.Length - 1)              {                m_cache[CountdownCurrentIndexCacheName] = 0;              }              else              {                m_cache[CountdownCurrentIndexCacheName] = nCountdownCurrentIndex + 1;              }            }              return m_snIntervalSecond[nCountdownCurrentIndex];         }         catch (Exception __error)          {            //如果需要记录错误日志的，可以记录到这里，我这里没有加            //log.Error("功能介绍GetCountdownAddedSecond：" + __error.Message);            if (nCountdownCurrentIndex > m_snIntervalSecond.Length - 1)            {              nCountdownCurrentIndex = m_snIntervalSecond.Length - 1;           }            return m_snIntervalSecond[nCountdownCurrentIndex];          }        }      }      }

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