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Rx .NET skip value changes by some scenario


I'm having trouble implementing a certain scenario with Rx. I have some code:

enum Status { NotConnected, Connecting, Connected }

class Provider
{
    public Status State { get => m_state; set => this.RaiseAndSetIfChanged(ref m_state, value); }
    public double Divergence { get => m_divergence; set => this.RaiseAndSetIfChanged(ref m_divergence, value); }
}

public void Run(Provider provider)
{
    provider.WhenAny(viewItem => viewItem.Divergence, change => change.Sender)
                                         .Throttle(TimeSpan.FromMilliseconds(500))
                                         .Subscribe(OnDivergenceChanged);
}

private void OnDivergenceChanged(Provider provider)
{
    ...
}

The status can be changed by the cyclogram NotConnected->Connecting->Connected.->NotConnected->Connecting...
Initial state is a NotConnected, the Divergence changes is not blocked.
I need to skip changing the Divergence value, starting from the moment of connection (state is Connecting) and ending 5 seconds after the "Connected" state is established.


Solution

  • This is a possible solution:

    IObservable<double> Divergence;
    IObservable<Status> State;
    IObservable<double> onDivergenceChanged = State
        .Select(state => state switch
        {
            Status.NotConnected => Divergence,
            Status.Connecting => Observable.Empty<double>(),
            Status.Connected => Observable.Timer(TimeSpan.FromSeconds(5)).Select(_ => Divergence).Switch(),
            _ => throw new ArgumentOutOfRangeException(nameof(state), state, null)
        })
        .Switch();
    

    It's quite declarative - for each status, either take: a) the stream of numbers; b) nothing; c) the numbers after a 5 second timer.