当文本框中的数字发生变化时，Oxyplot 图表不会刷新 (WPF)

Question

我尝试使用 MVVM 模式制作一个简单的 WPF 应用程序。它有一个文本框、一个文本块和一个 Oxyplot 图视图。 ** ViewModel 类**

public class ViewModel : INotifyPropertyChanged
{

    private PlotModel? plotModel;
    public PlotModel? PlotModel
    {
        get => plotModel;
        set { plotModel = value; OnPropertyChanged("PlotModel"); }
    }

    public LineSeries lineSeries { get; set; }

    private ObservableCollection<DataPoint>? _BestFitness;
    public ObservableCollection<DataPoint>? BestFitness
    {
        get => _BestFitness;
        set { _BestFitness = value; OnPropertyChanged(nameof(BestFitness)); }
    }

    public ViewModel()
    {
        PlotModel = new PlotModel();
        plot_curve();
    }

    private double _finish;
    public double Finish
    {
        get => _finish;
        set {
            _finish = value;
            OnPropertyChanged("Finish");
            OnPropertyChanged("PlotModel");
            PlotModel?.InvalidatePlot(true);
        }
    }

    public void plot_curve() {
        Model model = new();
        PlotModel?.Series.Clear();
        lineSeries = new();
        MessageBox.Show(Finish.ToString());
        BestFitness = new();
        for (double x = 0.0; x <= 5.0; x += 0.1)
            BestFitness.Add(new DataPoint(x, model.curve(x, 2)));
        BestFitness.Add(new DataPoint(5.1, model.curve(Finish, 2)));
        lineSeries.ItemsSource = BestFitness;
        PlotModel?.Series.Add(lineSeries);
        PlotModel?.InvalidatePlot(true);
    }

    public event PropertyChangedEventHandler? PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

XAML

<oxy:PlotView 
    BorderBrush="Black" 
    x:Name="Plot1" 
    Model="{Binding PlotModel}"
    Margin="10,10,10,90" 
    BorderThickness="1,1,1,1" 
    Opacity="1.0" 
    Grid.ColumnSpan="3" 
    FontSize="14" 
    Grid.Column="3">
</oxy:PlotView>
<TextBox Grid.Column="2" HorizontalAlignment="Left" Margin="10,57,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"
         Text="{Binding Finish, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"/>
<TextBlock Grid.Column="2" HorizontalAlignment="Left" Margin="10,77,0,0" Text="{Binding Finish}"/>

我尝试通过添加名为“完成”的点来刷新图表。使用文本框输入“完成”。我使用 INotifyPropertyChanged、ObservableCollection、InvalidatePlot(true)，但它不起作用。 textBox-textBlock 绑定工作正常，我可以在 textBlock 中看到 Finish 值。我在刷新图表的代码中缺少什么？

Answer 1

如果当 Finsih 点发生变化时 dataPoint 应该更新，那么你必须更改集合：

private double _finish;
public double Finish
{
    get => _finish;
    set 
    {
        _finish = value;
        BestFitness.RemoveAt(BestFitness.Count - 1);
        BestFitness.Add(new DataPoint(5.1, model.curve(_finish, 2)));
        OnPropertyChanged("Finish");
        OnPropertyChanged("PlotModel");
        PlotModel?.InvalidatePlot(true);
    }
}