cellBorderColor property

The color which fills the border of every calendar cells in SfCalendar.

Defaults to null.

Using a SfCalendarTheme gives more fine-grained control over the appearance of various components of the calendar.

See also:

• SfCalendarTheme, to handle theming with calendar for giving consistent look.
• backgroundColor, which fills the background of the calendar.
• Knowledge base: How to customize the cell border

Widget build(BuildContext context) {
   return Container(
     child: SfCalendar(
       view: CalendarView.day,
       cellBorderColor: Colors.grey,
     ),
   );
 }