Get the updated position value of a dragable BoxAnnotation with DateTime axis

Hello,
I am trying to add a BoxAnnotation with MVVM pattern where the X-Axis is a DateTime axis. The annotation can be dragged into the X-direction. I need to know the DateTime of each position while dragging and also the final position(DateTime) of the BoxAnnotation when the drag Ended. I am listening to the DragDelta and DragEnded events in ViewModel. But here I couldn’t able to get the DateTime from X1 and X2 of that annotation model. I am sharing some snippets of my code. Can you please let me know how I can achieve this?

In xaml:

<Style x:Key="_boxAnnotationStyle" BasedOn="{StaticResource AnnotationBaseStyle}" TargetType="scichart:BoxAnnotation">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="scichart:BoxAnnotation">
                    <Border x:Name="PART_BoxAnnotationRoot"
              Margin="{TemplateBinding Margin}"
              Background="{TemplateBinding Background}"
              BorderBrush="{TemplateBinding BorderBrush}"
              BorderThickness="{TemplateBinding BorderThickness}"
              CornerRadius="{TemplateBinding CornerRadius}" />
                </ControlTemplate>
            </Setter.Value>
        </Setter>
</Style>
<scichart:SciChartSurface x:Name="GraphSurface"
                 Annotations="{scichart:AnnotationsBinding ItsAnnotations}">

                <scichart:SciChartSurface.XAxis>
                    <scichart:DateTimeAxis x:Name="GraphXAxis"
                                           VisibleRange="{Binding ItsTimeVisibleRange, Mode=TwoWay}" />
                </scichart:SciChartSurface.XAxis>

                <scichart:SciChartSurface.YAxes>
                    <scichart:NumericAxis x:Name="GraphYAxis"
                                          VisibleRange="0, 10" />

                </scichart:SciChartSurface.YAxes>
 </scichart:SciChartSurface>

In ViewModel.cs

{
    private DateRange _timeVisibleRange;
    private ObservableCollection<IAnnotationViewModel> _annotations;
    private IAnnotationViewModel _boxAnnotation;
    public ObservableCollection<IAnnotationViewModel> ItsAnnotations
    {
        get
        {
            return _annotations;
        }
    }
    public DateRange ItsTimeVisibleRange
    {
        get { return _timeVisibleRange; }
        set
        {
            if (_timeVisibleRange == value) return;
            _timeVisibleRange = value;
            RaisePropertyChanged(() => ItsTimeVisibleRange);
        }
    }
    .
    .
    .
    _boxAnnotation = new BoxAnnotationViewModel()
        {
            IsEditable = true,
            DragDirections = SciChart.Charting.XyDirection.XDirection,
            X1 = DateTime.UtcNow.AddSeconds(300),
            X2 = DateTime.UtcNow,
            Y1 = 0,
            Y2 = 8,
            StyleKey = "_boxAnnotationStyle"
        };

     _annotations = new ObservableCollection<IAnnotationViewModel>() { };
     _annotations.Add(_boxAnnotation );

     _captureTimeRangeSelectorAnnotation.DragDelta += OnDrag;
     _captureTimeRangeSelectorAnnotation.DragEnded += DragEnded;
       .
       .
       .
    private void DragEnded(object sender, EventArgs e)
    {
         var boxAnnotationModel = sender as BoxAnnotationViewModel;
          // Need to know the DateTime value of X1 and X2
    }
    private void OnDrag(object sender, AnnotationDragDeltaEventArgs e)
    {
         var boxAnnotationModel = sender as BoxAnnotationViewModel;
         // Need to know the DateTime value of X1 and X2
    }
    .....
    .....
}