MVVM and SelectedPointMarkers - struggling to access Coordinates of selected point inside ViewModel

Hi Sean,

It’s possible to solve by inheriting the DataPointSelectionModifier and creating your own dependency property for SelectedPointMarkers

public class DataPointSelectionModifierExtended : DataPointSelectionModifier
{
    public static readonly DependencyProperty AllSelectedPointMarkersProperty = DependencyProperty.Register
        (nameof(AllSelectedPointMarkers),
        typeof(ObservableCollection<DataPointInfo>),
        typeof(DataPointSelectionModifierExtended),
        new PropertyMetadata(new ObservableCollection<DataPointInfo>()));

    public ObservableCollection<DataPointInfo> AllSelectedPointMarkers
    {
        get => (ObservableCollection<DataPointInfo>)GetValue(AllSelectedPointMarkersProperty);
        set => SetValue(AllSelectedPointMarkersProperty, value);
    }

    public DataPointSelectionModifierExtended()
    {
        SelectedPointMarkers.CollectionChanged += OnCollectionChanged;
    }

    private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        switch (e.Action)
        {
            case NotifyCollectionChangedAction.Add:
                e.NewItems.Cast<DataPointInfo>().ForEachDo(p => AllSelectedPointMarkers.Add(p));
                break;

            case NotifyCollectionChangedAction.Reset:
                AllSelectedPointMarkers.Clear();
                break;

            case NotifyCollectionChangedAction.Remove:
                e.OldItems.Cast<DataPointInfo>().ForEachDo(p => AllSelectedPointMarkers.Remove(p));
                break;

            case NotifyCollectionChangedAction.Replace:
            case NotifyCollectionChangedAction.Move:
            default: throw new NotImplementedException();
        }
    }
}

Best regards,
Dmytro