lowValueMapper property Null safety

ChartIndexedValueMapper<num>? lowValueMapper
final

Field in the data source, which is considered as low value for the data points.

Defaults to null.

Widget build(BuildContext context) {
   return SfCartesianChart(
     series: <RangeColumnSeries<SalesData, num>>[
       RangeColumnSeries<SalesData, num>(
         dataSource: <SalesData>[
           SalesData(2005, 24, 16),
           SalesData(2006, 22, 12),
           SalesData(2007, 31, 18),
         ],
        xValueMapper: (SalesData data, _) => data.year,
        lowValueMapper: (SalesData data, _) => data.low,
        highValueMapper: (SalesData data, _) => data.high,
       ),
     ],
   );
}
class SalesData {
  SalesData(this.year, this.high, this.low);
    final num year;
    final num high;
    final num low;
}

Implementation

final ChartIndexedValueMapper<num>? lowValueMapper;