Microsoft Graph API CalendarView vs Microsoft EWS CalendarView

Question

In EWS I can query a calendar with DateTime.Now and to only get the currently active events.

DateTime filterStartDate = DateTime.Now;
DateTime filterEndDate = filterStartDate.Date.AddDays(1).AddSeconds(-1);
CalendarView ccView = new CalendarView(filterStartDate, filterEndDate);

But it does not seem to work with MS Graphi API, where if the event started before my start filter, it won't show up

var queryOptions = new List<QueryOption>()
    {
        new QueryOption("startDateTime", filterStartDate.ToString("s")),
        new QueryOption("endDateTime",  filterEndDate .ToString("s"))
     };

 var res = await _graphClient.Users[roomSMTP].CalendarView
      .Request(queryOptions)
      .Header("Prefer", $"outlook.timezone=\"{_outlookTimeZone}\"")
      .Select("start,end,subject,organizer,id").GetAsync();

Is this by design or am I missing some sort of filter?

Any help would be appreciated.

Answer 1

From the documentation :

The values of startDateTime and endDateTime are interpreted using the timezone offset specified in the value and are not impacted by the value of the Prefer: outlook.timezone header if present. If no timezone offset is included in the value, it is interpreted as UTC.

I don't know if you are trying out edge cases but maybe you should use .ToString("o") (see here ).

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And do you know that your code returns IUserCalendarViewCollectionRequest and that you need to iterate over the calendarViewPages and get the results for every page?