Appointment Event
Calendar Appointments for Xamarin exposes the following event:
AppointmentTapped(AppointmentTappedEventArgs): Occurs when you tap over a specific appointment when in DayView or MultiDayView mode. It can be used to get all the information regarding the appointment.
AppointmentTapped Example
First you need to set the ViewMode to Day:
calendar.ViewMode = CalendarViewMode.Day;
Eventually, you can utilize the event:
calendar.AppointmentTapped += (sender, e) =>
{
Application.Current.MainPage.DisplayAlert(e.Appointment.Title, e.Appointment.Detail, "OK");
};