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Mouse interaction with LegendModifier

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I would like to allow user click on Legend and highlight the corresponding Series on the chart but I don’t know if this feature is supported or not.

I tried to add mouse events to the Legend Modified but it seems like mouse events are not triggered

This is the simple code that I am using

<s:LegendModifier x:Name="chlLegend" ShowLegend="True" LegendPlacement="Top" Orientation="Horizontal" MouseDown="chlLegend_MouseDown" ScrollViewer.HorizontalScrollBarVisibility="Auto" />

Before investigating more I would like to ask you if you have any hints which is the correct way to implement this behavior.
Is the LegendModifier suitable for this or should I override instead the Legend Control Template?

Thank you in advance for the support

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Best Answer

Yes the property you want to change is BaseRenderableSeries.LegendMarkerTemplate

Here is the default for line:

<DataTemplate x:Key="DefaultLegendMarkerTemplate" DataType="r:BaseRenderableSeries">
    <Line VerticalAlignment="Center"
          Stroke="{Binding SeriesColor,
                           Converter={StaticResource ColorToBrushConverter}}"
          Y2="0.5" />

and for Scatter:

<DataTemplate x:Key="ScatterSeriesLegendMarkerTemplate" DataType="r:XyScatterRenderableSeries">
        <Viewbox HorizontalAlignment="Center" Stretch="Uniform">
            <r:TemplatableControl Template="{Binding PointMarker.PointMarkerTemplate}" />

and for Mountain:

<DataTemplate x:Key="MountainSeriesLegendMarkerTemplate" DataType="r:FastMountainRenderableSeries">
    <Border BorderBrush="{Binding SeriesColor, Converter={StaticResource ColorToBrushConverter}}" BorderThickness="{Binding StrokeThickness, Converter={StaticResource DoubleToThicknessConverter}}">
        <Rectangle Fill="{Binding AreaBrush}" Stretch="Fill" />

I suggest binding something in there to BaseRenderableSeries.StrokeThickness.

Was there anything else you needed to know?

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Thank you Andrew for the support all clear now.

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Hi Marco,

Take a look at our tutorial on Custom Legend with Color Picker and Custom Point Markers. This shows you how to proide a LegendItemTemplate with a number of options.

Each Row in the Legend binds to a SeriesInfo derived type. SeriesInfo lets you access the RenderableSeries that the legend row represents.

So, using the above tutorial, you should be able to modify the template to have a checkbox to manipulate SeriesInfo.RenderableSeries.IsVisible.

Let me know if this helps!

Best regards,

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Thank you Andrew the link was helpful, I ovveride the default template and added a MouseEvent on the PointMarker that I can use to change the Stroke property of linked RenderableSeries.

                            <s:PointMarker Margin="5,0,0,0"
                                       DataContext="{Binding RenderableSeries}"
                                       DeferredContent="{Binding LegendMarkerTemplate}"
                                       Visibility="{Binding ShowSeriesMarkers, RelativeSource={RelativeSource AncestorType=s:SciChartLegend}, Converter={StaticResource BooleanToVisibilityConverter}}" />

What I did not understand yet is how to increase the thickness also on the line in the Legend.

Can you please share the PointMarker default WPF template so that I can override also that?
I don’t want to add or change the point marker but only increase the thickness of the line. (screenshot)

Thank you in advance.

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