OxyPlot触发LineSeries颜色更改通知

Question

I have an oxyplot, and a listbox with ColorPickers to select the LineSeries colors.

• The ColorPickers are bound to the LineSeries through a value converter (I could not use the oxyplot default color converter, because the ColorPickers use nullable Color-s, so I had to "customize" the OxyPlot.Wpf.OxyColorConverter)
• The color binding works in both directions: if I change the color in the ColorPickers, first the ConvertBack and then the Convert function is called. The LineSeries color and the ColorPicker colors are set.
• At startup, I add the LineSeries to the PlotModel.Series (see below)
• After that, before the first DataPoints would be added, the ColorConverter.Convert function is called, with a value = {A:0, B:1, G:0, R:0}. This sets the ColorPicker colors to some kind of transparent (the LineSeries colors do not change)

I guess, the problem is, that the LineSeries that are added to the PlotModel.Series do not have a valid color set, before I add DataPoints to them.

• I did not find any RaisePropertyChanged or similar notifications on the Series or LineSeries instances.
• I tried to call RaisePropertyChanged("PlotModel"); after the first datapoint - does not help nor with any combination of "PlotModel.Series.Color"
• The PlotModel.InvalidatePlot(true); is called after each data point, but this does not notify the ColorPickers of color change.

So the question is: how can I make the ColorPickers take up the valid colors of the LineSeries after startup, before the ColorPickers are manually changed?

I would like to avoid setting the colors manually at instantiation, right now I'm happy with the colors the PlotModel assigns to them.

OxyPlot and ListBox:

<oxy:PlotView Grid.Column="0" Grid.Row="0" x:Name="plot1" Model="{Binding PlotModel}"/>
...
<ListBox Grid.Column="1" Grid.Row="0" ItemsSource="{Binding PlotModel.Series}">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <CheckBox IsChecked="{Binding Path=IsVisible}" />
                <xctk:ColorPicker Width="30" ShowDropDownButton="False" SelectedColor="{Binding Path=Color, Mode=TwoWay,  UpdateSourceTrigger=PropertyChanged, Converter={StaticResource ColorConverter}}" Opacity="1" ShowRecentColors="True"/>
                <TextBlock Text="{Binding Path=Title}"/>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

The ColorConverter XAML resource:

<local:ColorConverter x:Key="ColorConverter"></local:ColorConverter>

And the C# code:

[ValueConversion(typeof(OxyColor), typeof(Rect))]
class ColorConverter : IValueConverter
{      
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is OxyColor)
        {
            var color = (OxyColor)value;
            if ((targetType == typeof(Color)) || (targetType == typeof(Color?)))
            {
                return color.ToColor();
            }

            if (targetType == typeof(Brush))
            {
                return color.ToBrush();
            }
        }

        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (targetType == typeof(OxyColor))
        {
            if (value is Color)
            {
                var color = (Color)value;
                return OxyColor.FromArgb(color.A, color.R, color.G, color.B);
            }

            if (value is SolidColorBrush)
            {
                var brush = (SolidColorBrush)value;
                Color color = brush.Color;
                return OxyColor.FromArgb(color.A, color.R, color.G, color.B);
            }
        }

        return null;
    }

}

This is how I add new LineSeries dynamically:

LineSeries l = new LineSeries { LineStyle = LineStyle.Solid, Title = title };
PlotModel.Series.Add(l);

Answer 1

Modifying the LineSeries instantiation works:

LineSeries l = new LineSeries { LineStyle = LineStyle.Solid, Title = title, Color = PlotModel.DefaultColors[PlotModel.Series.Count] };

Is there another way? Eg some kind of color property change event?