当更改viewmodel2中的依赖项属性时，viewmodel1中的属性不会更新。

Question

我正在使用MVVM模式创建WPF SciChart应用程序（仍在学习中）。 在此应用程序中，我正在创建一个编辑功能，其中用户在屏幕上绘制一个框，并将两行添加到图表viewModel中类型为IAnnotationViewModel的ObservableCollection中。

然后我有一个修改器类，该类继承了ChartModifierBase（访问数据系列，轴等）。在此类中，我创建了一个依赖项属性，该属性将2种方式绑定到图表viewModel中的ObservableCollection。将线添加到图表表面时，dp会更新，但是图表viewModel中的集合不是。我是否缺少某些东西...我希望如此，以便我不确定如何实现PropertyChangedCallback委托。请参见下面的代码

  <s:SciChartSurface Annotations="{s:AnnotationsBinding Annotations}"
                           s:SciChartGroup.VerticalChartGroup="myGroup" 
                           Padding="5" 
                           x:Name="ChartTwo"
                           ZoomHistoryManager="{StaticResource ZoomHistoryManager}" 
                           RenderableSeries="{s:SeriesBinding ChartTwo,UpdateSourceTrigger=PropertyChanged}"> 
            <s:SciChartSurface.ChartModifier>
                <s:ModifierGroup s:MouseManager.MouseEventGroup="myCustomGroup">   
                    <modifiers:SelectionModifier IsEnabled="{Binding ElementName=SelectionModifierToggle ,Path=IsChecked}"  
                                                 Annotations="{Binding Path = Annotations, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                          SelectionPolygonStyle="{StaticResource SelectionStyle}"/>    
                </s:ModifierGroup>
            </s:SciChartSurface.ChartModifier>
        </s:SciChartSurface>


public class ChartEditViewModel
{
 private ObservableCollection<IAnnotationViewModel> _annotations = new ObservableCollection<IAnnotationViewModel>();

    public  ObservableCollection<IAnnotationViewModel> Annotations
    {
        get { return _annotations; }
        set { _annotations = value; OnPropertyChanged("Annotations"); }
    }
}

 public class VerticalLineViewModel : VerticalLineAnnotationViewModel
{
    public override Type ViewType
    {
        get { return typeof(VerticalLineAnnotation); }
    }        
}

 public class SelectionModifier : ChartModifierBase, IDialogRequestClose
{  
    private IList<IPointMetadata> _seriesPointMetadata;  //selected series metadata
    MoveBlockViewModel moveBlockViewModel;
    IDialogService dialogService;

    public ObservableCollection<IAnnotationViewModel> Annotations
    {
        get { return (ObservableCollection<IAnnotationViewModel>)GetValue(AnnotationsProperty); }
        set { SetValue(AnnotationsProperty, value); }
    }

    // Using a DependencyProperty as the backing store for Annotations.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty AnnotationsProperty =
        DependencyProperty.Register("Annotations", typeof(ObservableCollection<IAnnotationViewModel>), typeof(SelectionModifier), new PropertyMetadata());

    public Style SelectionPolygonStyle
    {
        get { return (Style)GetValue(SelectionPolygonStyleProperty); }
        set { SetValue(SelectionPolygonStyleProperty, value); }
    }


    // Using a DependencyProperty as the backing store for SelectionPolygonStyle.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty SelectionPolygonStyleProperty =
        DependencyProperty.Register("SelectionPolygonStyle", typeof(Style), typeof(SelectionModifier), new PropertyMetadata(default(Style)));

    ///<summary>
    ///reticule
    ///</summary>
    private Rectangle _rectangle;
    private bool _isDragging;
    private Point _startPoint;
    private Point _endPoint;
    public VerticalLineViewModel Line1 = new VerticalLineViewModel();
    public VerticalLineViewModel Line2 { get; set; }
    private IRenderableSeries _selectedSeries;

    public event EventHandler<DialogCloseRequestedEventArgs> CloseRequested;

    public SelectionModifier()
    {

    }

 public override void OnModifierMouseUp(ModifierMouseArgs e)
    {
        if (!_isDragging) return;

        base.OnModifierMouseUp(e);

        var ptTrans = GetPointRelativeTo(e.MousePoint, ModifierSurface);

        _endPoint = SetReticulePosition(_rectangle, _startPoint, ptTrans, e.IsMaster);

        double distanceDragged = PointUtil.Distance(_startPoint, ptTrans);
        if (distanceDragged > 10.0)
        {
            e.Handled = true;
        }

        _isDragging = false;

        if (e.IsMaster) ModifierSurface.ReleaseMouseCapture();

        var startX = _selectedSeries.XAxis.GetCurrentCoordinateCalculator().GetDataValue(_startPoint.X);
        var endX = _selectedSeries.XAxis.GetCurrentCoordinateCalculator().GetDataValue(_endPoint.X);

        var startY = _selectedSeries.YAxis.GetCurrentCoordinateCalculator().GetDataValue(_startPoint.Y);
        var endY = _selectedSeries.YAxis.GetCurrentCoordinateCalculator().GetDataValue(_endPoint.Y);

        //XAxis.AnimateVisibleRangeTo(new DoubleRange(startX, endX),TimeSpan.FromMilliseconds(300));

        startX = (int)Math.Round(startX, 1);
        endX = (int)Math.Round(endX, 1);


        var startIndex = _selectedSeries.DataSeries.XValues.IndexOf(startX);
        var endIndex = _selectedSeries.DataSeries.XValues.IndexOf(endX);



        //YAxis.AnimateVisibleRangeTo(new DoubleRange(startY, endY),TimeSpan.FromMilliseconds(300));
        if (_startPoint != _endPoint)
        {
            if (startIndex == -1)
                startIndex = 0;
            if (endIndex == -1)
                endIndex = _selectedSeries.DataSeries.XValues.Count - 1;



            Line1 = AddVerticalLine((double)_selectedSeries.DataSeries.XValues[startIndex]);
            Line2 = AddVerticalLine((double)_selectedSeries.DataSeries.XValues[endIndex]);

            X1 = (double)Line1.X1;


            Line1.PropertyChanged += Line_PropertyChanged;
            Line2.PropertyChanged += Line_PropertyChanged;

            Annotations.Add(Line1);
            Annotations.Add(Line2);

            for (int i = startIndex; i <= endIndex; i++)
            {
                if (i > -1)
                    _seriesPointMetadata[i].IsSelected = true;
            }   

        }


        ParentSurface.InvalidateElement();
        ClearReticule();


    }