private void _timer_Elapsed(object sender, ElapsedEventArgs e) { foreach (KeyValuePair <string, IVolatileToken> token in timeCache) { if (!token.Value.IsCurrent) { IVolatileToken _token = new AbsoluteExpirationToken(this, TimeSpan.Zero); MemcachedHelper.GetInstance().Remove(token.Key); timeCache.TryRemove(token.Key, out _token); } } }