The selected event for the LegendModifier checkbox

Hi Yu Dexiu,

Thanks for your question.
There isn’t such a callback on the LegendModifier.

However, since Legend checkboxes can hide or show a RenderableSeries, you can subscribe to IsVisibleChanged event on a RenderableSeries. It will be fired when a user changes series visibility through the Legend.

Alternatively, you can re-template the default Legend and have a binding on Checkboxes that will be triggered when they are checked/unchecked.

You can find more info about Legend customization here:
https://www.scichart.com/documentation/win/current/webframe.html#LegendModifier.html

With best regards,
Lex S., MSEE
SciChart Technical Support Engineer

Is your question related to WPF (Windows charts) or JS (JavaScript charts)?

In SciChart.js there is a mechanism to get a callback on legend checkbox changed. See the LegendModifier documentation.

Subscribing to Checkbox Checked Changed

As well as subscribing to BaseRenderableSeries.isVisibleChanged, you
can now subscribe to LegendModifier.isCheckedChanged event. This can
be done either in the constructor options to LegendModifier or after
creation.

const legend = new LegendModifier({
      showCheckboxes: true,
      showSeriesMarkers: true,
      showLegend: true,
      // Subscribe to checked changed here
      isCheckedChangedCallback: (series, isChecked) => {
          console.log(`Option 1: Legend item ${series.type} isChecked=${isChecked}`);   
      }
  });
  // Or here after instantiation
  legend.isCheckedChanged.subscribe((args) => {
      console.log(`Option 2: Legend item ${args.series.type} isChecked=${args.isChecked}`);
  });
  // Add the legend to the chart
  sciChartSurface.chartModifiers.add(legend);