This API from ASP.NET RadScheduleView does not have an alternative in RadScheduleview for WPF.
To achieve the desired functionality you can get all appointments for a certain period by using GetOccurrences
method. If you loop through the AppointmentsSource of the ScheduleView and call this method for each appointment, you'll get the needed result. After that you will be able to count them and display them where is suitable for you.
Also I suggest you review one of our SDK example
where a similar approach is illustrated.
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