You can try binding to an empty DataTable:

DataTable dt = new DataTable();
dt.Columns.Add("start", typeof(DateTime));
dt.Columns.Add("end", typeof(DateTime));
dt.Columns.Add("name", typeof(string));
dt.Columns.Add("id", typeof(string));

DayPilotCalendar1.DataSource = dt;
DayPilotCalendar1.DataBind();