Create appointment with custom properties in EWS

Question

I try to add a custom property to created appointments like this:

var newEvent = new Appointment(service)
        {
            Start = start,
            End =          


        

Answer 1

You need to first Create a property set, add the extended property you want to load to that property set. Then tell EWS you want that property returned when you execute the FindAppointment method see https://msdn.microsoft.com/en-us/library/office/dd633697(v=exchg.80).aspx eg in your example

        PropertySet YourProperyset = new PropertySet(BasePropertySet.FirstClassProperties);
        var extendendProperty = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.Address, "organizer",MapiPropertyType.String);
        YourProperyset.Add(extendendProperty);
        var folderId = new FolderId(WellKnownFolderName.Calendar, new Mailbox(userName));
        var calendar = CalendarFolder.Bind(service, folderId);
        var calendarView = new CalendarView(start, stop);
        calendarView.PropertySet = YourProperyset;
        return calendar.FindAppointments(calendarView).ToList();