Is there no API that basically provides?
It looked okay at first because it was implemented like the code below. However, pressing Next Button will not update on days other than that month.
private void radCalendar1_ElementRender(object sender, RenderElementEventArgs e)
if (e.Day.Date.Year == DateTime.Now.Year
&& e.Day.Date.Month == DateTime.Now.Month
&& e.Day.Date.DayOfWeek == DayOfWeek.Sunday)
e.Element.ForeColor = Color.Red;
After, Next Button Click