我的线程设计是好还是不好

我是一个新手，我是一个初级开发人员:)所以我想有很多错误。我的场景是这样的:

• 查看数据库，如果有数据将被发送，获取这些数据
• 将此数据添加到队列
如果队列不为空，取消下一个队列并发送它
• 和等待10秒来自另一个线程的msj，
• 如果msj停止等待并传递到队列中的下一个消息
• 如果msj没有出现，请重试10秒，等待2次
• 如果仍然没有消息传递给下一个消息，直到消息发送完毕。
• 然后再次查看数据库中的msgs

我正在尝试这样做:

    private Thread ReceiveThread;
    private Thread SendThread;
    internal static Thread ServiceThread;

this 3 threads

    ReceiveThread = new Thread(ReceiveTask);
    ReceiveThread.Start();
    ServiceThread = new Thread(SerAutoThread.SendServiceMsg);
    ServiceThread.Start();
    SendThread = new Thread(SendTask);
    SendThread.Start();

.

 class SerAutoThread
    {
    internal static object[] NextService;
    public static readonly object _locker = new object();
    internal static Queue<object[]> Services;
    internal static int sendingTime = 0;
    private static DatabaseFirebird DB;
    internal static void SendServiceMsg()
    {
        DB = new DatabaseFirebird();
        DB.Open(ConnectionStr);
        Services = new Queue<object[]>();
        while (true)
        {
            if (Services.Count != 0)
            {
                SetNextSerAndSend();
            }
            else
            {
                CheckAndSetServices();
            }
        }
    }

     private static void SetNextSerAndSend()
    {
        NextService = Services.Dequeue();
        for (int j = 0; j < 4; j++)
            {
                if (sendingTime == TRANSMITTED)
                {
                   //pass to next msg
                   sendingTime = 0;
                   j = NEXTMSG;
                }
                else if (sendingTime < 3)
                {
                    sendingTime++;
                    Byte[] data = SetNextPckage();
                    DeviceManager.MessageSendQueue.PostItem(new SendMessage("UDPCmd",
                NextService[(int)NextMsg.DeviceId].ToString(), 
                data, data.Length));
                    MyDebug.WriteLine("Sended...");
                    lock (_locker)
                    {
                        Monitor.Wait(_locker, TimeSpan.FromSeconds(10));
                    }
                }
                else 
                {
                    // pass to next msg
                    j = NEXTMSG;
                }
            }
    }
}

.

private void ReceiveTask()
        {
            ReceiveMessage receiveMsg;
            while (true)
            {
                receiveMsg = Com.MessageReceiveQueue.GetItem(-1);
                SerAutoThread.sendingTime
                        = SerAutoThread.TRANSMITTED;
                    lock (SerAutoThread._locker)
                    {
                        Monitor.Pulse(SerAutoThread._locker);
                    }
            }
        }

…

 private void SendTask()
        {
            SendMessage msg;
            while (true)
            {
                msg = MessageSendQueue.GetItem(-1);
                String rtrn = PushData(msg);
            }
        }

是否线程安全。我不确定是设计有问题还是我在其他地方做错了?谢谢…