小编ret*_*ent的帖子

我有一个同步哈希表,我定期从中删除一些条目.多个线程运行此代码.所以我锁定了整个foreach,但我仍然有时会得到InvalidOperationException:Collection被修改了......在Hashtable.HashtableEnumerator.MoveNext() - 即在foreach循环中.我究竟做错了什么？锁不够？

private static readonly Hashtable sessionsTimeoutData = Hashtable.Synchronized(new Hashtable(5000));


private static void ClearTimedoutSessions()
{
    List keysToRemove = new List();
    long now = DateTime.Now.Ticks;
    lock (sessionsTimeoutData)
    {
        TimeoutData timeoutData;
        foreach (DictionaryEntry entry in sessionsTimeoutData)
        {
            timeoutData = (TimeoutData)entry.Value;
            if (now - timeoutData.LastAccessTime > timeoutData.UserTimeoutTicks)
                keysToRemove.Add((ulong)entry.Key);
        }
    }
    foreach (ulong key in keysToRemove)
        sessionsTimeoutData.Remove(key);
}