期限内に指定回数値が通過した時、その時の最新の値を出す

test_ofperiodcount

public static class ObserverExtensions
{
    /// <summary>
    /// periodの期間内にcount回数の値が通過した時、その時の最新の値を出す
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="self"></param>
    /// <param name="period"></param>
    /// <param name="count"></param>
    /// <param name="removeArrivedCache"></param>
    /// <returns></returns>
    public static IObservable<T> OfPeriodCount<T>(this IObservable<T> self, TimeSpan period, int count, bool removeArrivedCache = true)
    {
        return Observable.Create<T>(observer =>
        {
            var calles = new List<System.Reactive.Timestamped<T>>();
            self.Timestamp().Subscribe((x) =>
                {
                    calles.Add(x);
                    calles.RemoveAll((y) => x.Timestamp - y.Timestamp > period); // 期限切れ削除

                    if (calles.Count >= count)
                    {
                        observer.OnNext(x.Value);
                        if (removeArrivedCache)
                        {
                            calles.Clear();
                        }
                    }
                },
                (err) =>
                    observer.OnError(err),
                () =>
                    observer.OnCompleted()
                );
            return () => { };
        });
    }
}

public static class FormExtensions
{
    public static IObservable<MouseEventArgs> MouseDownAsObservable(this Form self)
    {
        return Observable.FromEvent<MouseEventHandler, MouseEventArgs>(
            h => (_, args) => h(args),
            h => self.MouseDown += h,
            h => self.MouseDown -= h);
    }
}


public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        this.MouseDownAsObservable()
            .OfPeriodCount(TimeSpan.FromMilliseconds(250), 2)
            .Subscribe((x) =>
            {
                this.label1.Text = "x:" + x.X + " y:" + x.Y;
            });
    }
}