如何异步执行WhenAnyValue委托？

Question

如何异步执行WhenAnyValue委托？

3

我有这段代码，每当另一个属性更改时，它会生成一个“计算”或“输出”属性。派生属性生成正确，但由于 CreateBlurImage 执行时间较长，因此 UI 在其运行时会被冻结。

如何以异步方式实现相同的最终结果？

编辑：这是经过@Shane建议后我代码的当前版本，但UI仍然会在所有处理完成之前保持冻结。请注意，如果相关联的更新很多，那么可能会有所影响：

    public ColetaIsis Model { get; private set; }

    public string NomePaciente { get { return Model?.NomePaciente; } }
    public DateTime DataRealização { get { return Model.DataRealização; } }



    public BitmapSource Listras
    {
        get { return _listras; }
        set { this.RaiseAndSetIfChanged(ref _listras, value); }
    }
    BitmapSource _listras;


    public double[,] Grayscale { get { return _grayscale.Value; } }
    readonly ObservableAsPropertyHelper<double[,]> _grayscale;

    public double[,] BlurMenor { get { return _blurMenor.Value; } }
    readonly ObservableAsPropertyHelper<double[,]> _blurMenor;

    public double[,] BlurMaior { get { return _blurMaior.Value; } }
    readonly ObservableAsPropertyHelper<double[,]> _blurMaior;

    public double[,] Diferença { get { return _diferença.Value; } }
    readonly ObservableAsPropertyHelper<double[,]> _diferença;


    public BitmapSource FiltradaMenor { get { return _filtradaMenor?.Value; } }
    readonly ObservableAsPropertyHelper<BitmapSource> _filtradaMenor;

    public BitmapSource FiltradaMaior { get { return _filtradaMaior?.Value; } }
    readonly ObservableAsPropertyHelper<BitmapSource> _filtradaMaior;

    public BitmapSource ImagemDiferença { get { return _imagemDiferença?.Value; } }
    readonly ObservableAsPropertyHelper<BitmapSource> _imagemDiferença;


    public IEnumerable<ScatterPoint> Picos => _picos;
    IEnumerable<ScatterPoint> _picos;








    // CONSTRUTOR
    public ColetaIsisViewModel(ColetaIsis model) 
    {
        this.WhenAnyValue(x => x.Listras)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(im => GetArray.FromChannels(im, 0, 1))
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.Grayscale, out _grayscale, scheduler:RxApp.MainThreadScheduler);

        this.WhenAnyValue(x => x.Grayscale)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(ar => Gaussian.GaussianConvolution(ar, 1.5))
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.BlurMenor, out _blurMenor, scheduler: RxApp.MainThreadScheduler);

        this.WhenAnyValue(x => x.BlurMenor)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(ar => Gaussian.VerticalGaussianConvolution(ar, 5))
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.BlurMaior, out _blurMaior, scheduler: RxApp.MainThreadScheduler);

        this.WhenAnyValue(x => x.BlurMenor, x => x.BlurMaior)
            .Where(tuple => tuple.Item1 != null && tuple.Item2 != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(tuple => ArrayOperations.Diferença(tuple.Item1, tuple.Item2))
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.Diferença, out _diferença, scheduler: RxApp.MainThreadScheduler);



        this.WhenAnyValue(x => x.BlurMenor)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(ar => { ConversorImagem.Converter(ar, out BitmapSource im); return im; })
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.FiltradaMenor, out _filtradaMenor, scheduler: RxApp.MainThreadScheduler);

        this.WhenAnyValue(x => x.BlurMaior)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(ar => { ConversorImagem.Converter(ar, out BitmapSource im); return im; })
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.FiltradaMaior, out _filtradaMaior, scheduler: RxApp.MainThreadScheduler);

        this.WhenAnyValue(x => x.Diferença)
            .Where(item => item != null)
            .ObserveOn(RxApp.TaskpoolScheduler)
            .Select(ar => { ConversorImagem.Converter(ar, out BitmapSource im); return im; })
            //.ObserveOn(RxApp.MainThreadScheduler)
            .ToProperty(this, x => x.ImagemDiferença, out _imagemDiferença, scheduler: RxApp.MainThreadScheduler);


        Model = model;

        Listras = Model.Listras;  // fires up the initial cascading updates
    }

- heltonbiker

1个回答

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- Shane Neuville · Accepted Answer

这些方法有哪些可行？这样一来，CreateBlurImage部分就可以在UIThread之外完成。

public MyClass()
{
    this.WhenAnyValue(x => x.StripedImage)
        .ObserveOn(RxApp.TaskpoolScheduler)
        .Select(im => CreateBlurImage(im))
        .ObserveOn(RxApp.MainThreadScheduler)
        .ToProperty(this, x => x.Filtered, out _filtered);
}

我相信在ToProperty上指定调度程序与上述方法是相同的。

public MyClass()
{
    this.WhenAnyValue(x => x.StripedImage)
        .ObserveOn(RxApp.TaskpoolScheduler)
        .Select(im => CreateBlurImage(im))
        .ToProperty(this, x => x.Filtered, out _filtered, scheduler:RxApp.MainThreadScheduler);
}