C＃线程同步

Question

I am developing an app for wp7. I required a synchronized read and write. So I created this class

public class SynchronizedPacketQueue
{
    [DataMember]
    public List<Packet> packetsQ;

    public SynchronizedPacketQueue()
    {
        packetsQ = new List<Packet>();
    }

    public int Count
    {
        get { return packetsQ.Count; }
        private set{}
    }


    public Packet Dequeue()
    {
        lock (packetsQ)
        {
            if (packetsQ.Count == 0)
            {
                Monitor.Wait(packetsQ);

            }
            Packet packet = packetsQ[0];
            packetsQ.RemoveAt(0);
            return packet;
        }
    }

    public void  Enqueue(Packet packet)
    {
        lock (packetsQ)
        {
            packetsQ.Add(packet);
            Monitor.Pulse(packetsQ);
        }
    }
}

Now my threadwrite enqueues packets in the queue and threadread reads from the queue.Both are infinite running threads. But i don't know some how threadwrite is blocked at packetQ.removeat(0).

Answer 1

I think you should create lock object and use it your lock

public class SynchronizedPacketQueue
   {
      [DataMember]
      public List<Packet> packetsQ;
      private object mylock = new object();

      public SynchronizedPacketQueue()
      {
        packetsQ = new List<Packet>();
      }

    public int Count
    {
        get { return packetsQ.Count; }
        private set{}
    }


    public Packet Dequeue()
    {
        lock (mylock)
        {
            if (packetsQ.Count == 0)
            {
                Monitor.Wait(mylock);

            }
            Packet packet = packetsQ[0];
            packetsQ.RemoveAt(0);
            return packet;
        }
    }

    public void  Enqueue(Packet packet)
    {
        lock (mylock)
        {
            packetsQ.Add(packet);
            Monitor.Pulse(mylock);
        }
    }
}