问OxyPlot WPF ViewMaximum

EN

using GalaSoft.MvvmLight.Command;
using OxyPlot;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication15
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
/// 
public class DataLoading
{
    public PlotModel PlotModel { get; set; }
    public ICommand TestCommand { get; set; }
    OxyPlot.Axes.LinearAxis X;
    OxyPlot.Axes.LinearAxis Y;
    private OxyPlot.Series.LineSeries FirstSeries;
    private OxyPlot.Series.LineSeries SecondSeries;
    private int i =0;
    public DataLoading()
    {
        TestCommand = new RelayCommand(()=>ShowActualPoints());
        PlotModel = new PlotModel();
        X = new OxyPlot.Axes.LinearAxis()
        {
            Position = OxyPlot.Axes.AxisPosition.Bottom,
            Minimum=1,
            Maximum=5
        };
        Y = new OxyPlot.Axes.LinearAxis()
        {
            Position = OxyPlot.Axes.AxisPosition.Left,
            IsPanEnabled = false
        };
        FirstSeries = new OxyPlot.Series.LineSeries();
        SecondSeries = new OxyPlot.Series.LineSeries();
        FirstLoad();

        PlotModel.Axes.Add(X);
        PlotModel.Axes.Add(Y);
        OxyPlot.Wpf.PlotView PV = new OxyPlot.Wpf.PlotView();
        PlotModel.Axes[0].AxisChanged += (o, e) =>
        {
            double LastPoint = (from y in FirstSeries.Points select y.X).Min();
            ShowActuals(LastPoint);
        };
    }
    public delegate void BeginUpdate();
    public void ShowActuals(double inputlastpoint)
    {

        if (inputlastpoint > PlotModel.Axes[0].ActualMinimum)
        {
            Debug.WriteLine("Need to load points");
            BeginUpdate BU = new BeginUpdate(SecondLoad);
            IAsyncResult result = BU.BeginInvoke(null,null);
        }
        else
        {
            Debug.WriteLine("No need to load points");
        }
    }

    private void FirstLoad()
    {
        FirstSeries.Points.Add(new DataPoint(1, 1));
        FirstSeries.Points.Add(new DataPoint(2, 2));
        FirstSeries.Points.Add(new DataPoint(3, 3));
        FirstSeries.Points.Add(new DataPoint(4, 3));
        FirstSeries.Points.Add(new DataPoint(5, 3));
        PlotModel.Series.Add(FirstSeries);
    }
    private void SecondLoad()
    {
        Random rnd = new Random();
        FirstSeries.Points.Insert(0,new DataPoint(--i, rnd.NextDouble()));
        System.Threading.Thread.Sleep(1000);
        PlotModel.InvalidatePlot(true);
    }
    private void ShowActualPoints()
    {
        Debug.WriteLine("Y:{0}",PlotModel.Axes[1].ActualMaximum);
        Debug.WriteLine("X:{0}", PlotModel.Axes[0].ActualMaximum);
        //Debug.WriteLine("Y:{0}", PlotModel.Axes[1].Act);
        //Debug.WriteLine("X:{0}", PlotModel.Axes[0].ActualMaximum);
        //Debug.WriteLine(PlotModel.Series[0].GetNearestPoint(new ScreenPoint(PlotModel.Axes[0].ActualMaximum, PlotModel.Axes[1].ActualMaximum), false));
    }
}
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext= new DataLoading();
    }
}