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Question

I'm using one thread to parse the packets and add to the list, then I'm using other thread to itinerate that list and parse the packet.

I can receive the packets and add them to the list, somehow the other thread is still using the outdated version of the list. I tried to use lock to read/write to it but is still happening.

private class SocketInformation
{
    public bool open { get; set; }
    private ConcurrentQueue<byte[]> packetReceiveQueue = new ConcurrentQueue<byte[]>();

    public ConcurrentQueue<byte[]> GetPacketReceiveQueue()
    {
        return packetReceiveQueue;
    }
}

private void NewConnection(StreamSocket socket)
{
    SocketInformation socketInformation = new SocketInformation();
    socketInformation.open = true;
    Task.Run(() => ReadPackets(socket, socketInformation));
    Task.Run(() => OnlineLoop(socket, socketInformation));
}

private async void ReadPackets(StreamSocket socket, SocketInformation socketInformation)
{
    // ...
    Debug.WriteLine("Packet received.");

    ConcurrentQueue<byte[]> packetReceiveQueue = socketInformation.GetPacketReceiveQueue();
    packetReceiveQueue.Enqueue(packet);
}

private async void OnlineLoop(StreamSocket socket, SocketInformation socketInformation)
{
    while (socketInformation.open)
    {
        ConcurrentQueue<byte[]> packetReceiveQueue = socketInformation.GetPacketReceiveQueue();

        for (int i = 0; i < packetReceiveQueue.Count; i++)
        {
            Debug.WriteLine("Parsing packet.");
            byte[] packet = packetReceiveQueue.ElementAt(i);
            ParsePacketSequence(socket, socketInformation, packet);
        }
    }
}

Console:

1. Packet received.
2. Packed added to the queue.
3. Parsing packet.
4. Packet received.
5. Packed added to the queue.
6. (Second packet not parsed, list outdated)

Answer 1

There are Thread-Safe Collections built-in to .net. Find the one that best suits your need. (Looks like ConcurrentQueue would be best - it's FIFO.)