lineType property

TrackballLineType lineType
final

Type of trackball line. By default, vertical line will be displayed. You can change this by specifying values to this property.

Defaults to TrackballLineType.vertical

Also refer TrackballLineType

Widget build(BuildContext context) {
   return Container(
       child: SfCartesianChart(
          trackballBehavior: TrackballBehavior(
          enable: true,
          lineType: TrackballLineType.horizontal
       ),
       ));
}

Implementation

final TrackballLineType lineType