c# - 带有 UDPClient.EndReceive 和 ref 远程端点参数的 Observable.FromAsyncPattern

Question

我正在学习 Reactive 扩展并尝试重构我的一些代码。

UDPClient.EndReceive 接受一个 ref IPEndPoint 参数，所以我目前有这个工作:

UdpClient receiverUDP = new UdpClient();
receiverUDP.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
receiverUDP.EnableBroadcast = true;
receiverUDP.Client.ExclusiveAddressUse = false;
receiverUDP.Client.Bind(new IPEndPoint(IPAddress.Any, 1234));

IPEndPoint ep = null;
var async = Observable.FromAsyncPattern<byte[]>(receiverUDP.BeginReceive, (i) => receiverUDP.EndReceive(i, ref ep));
var subscr = async().Subscribe(x => Console.WriteLine(ASCIIEncoding.ASCII.GetString(x)));

如果我的订阅者需要访问远程 IPEndPoint 怎么办？在我当前的版本中，我正在使用事件，并传回一个包含 byte[] 和 IPEndPoint 的自定义类。我这辈子都想不出如何用 Rx 做到这一点。

Answer 1

如果您已经为 byte[] 和 IPEndPoint 创建了包装类，为什么不使用 Select 将其作为序列返回:

private IObservable<RemoteData> GetRemoteDataAsync()
{
    return Observable.Defer(() => 
    {
        UdpClient receiverUDP = new UdpClient();
        receiverUDP.Client.SetSocketOption(SocketOptionLevel.Socket, 
            SocketOptionName.ReuseAddress, true);
        receiverUDP.EnableBroadcast = true;
        receiverUDP.Client.ExclusiveAddressUse = false;
        receiverUDP.Client.Bind(new IPEndPoint(IPAddress.Any, 1234));

        IPEndPoint ep = null;
        return Observable.FromAsyncPattern<byte[]>(
                   receiverUDP.BeginReceive, 
                   (i) => receiverUDP.EndReceive(i, ref ep)
               )()
               .Select(bytes => new RemoteData(bytes, ep));
    });
}