highlight bank holidays in scheduler

1. First you need the holiday data.
2. Add a BeforeCellRender event handler. This event is called once for each time cell. You should check the cell date (e.Start, e.End) here and compare it with the holiday data.
3. Set e.IsBusiness or e.BackgroundColor as needed. In CssOnly mode, it's better to use e.CssClass instead.

Example:

    protected void DayPilotScheduler1_BeforeCellRender(object sender, DayPilot.Web.Ui.Events.BeforeCellRenderEventArgs e)
    {
        if (IsHoliday(e.Start))
        {
            e.CssClass = "holiday_cell";
        }
    }

This will mark all holiday cells with .holiday_cell class. You need to provide your own IsHoliday() method.