c# - 如何异步执行 WhenAnyValue 委托(delegate)？

Question

每次另一个属性发生变化时，我都会使用此代码生成一个“已计算”或“输出”属性。派生属性已正确生成，但由于 CreateBlurImage 运行时间有点长，因此 UI 在运行时会卡住。

以异步方式获得相同最终结果的正确方法是什么？

根据@Shane 的一些建议，编辑这是我的代码的当前版本，但在所有处理完成之前，UI 仍然保持卡住状态。请注意，如果重要的话，有相当多的级联更新:

    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
    }

Answer 1

这些方法中的任何一种都行得通吗？这样 CreateBlurImage 部分就完成了 UIThread

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

或者我很确定在 ToProperty 上指定调度程序将与上面相同

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