Deleting calendar events with Microsoft Graph - Why do I need to call multiple times?

Question

After much investigation and beta-testing I have come up with the following approach to delete calendar events:

public async Task DeleteCalendarEvent         


        

Answer 1

If I use the $top option I can adjust the size of the pages and thus reduce the number of calls I need to make:

List<QueryOption> listQueryOptions = new List<QueryOption>()
{
    new QueryOption("$top", "50")
};

var oEvents = await _graphClient
                        .Me
                        .Calendars[oSettings.CalendarID]
                        .Events
                        .Request(listQueryOptions)
                        .Filter(strFilter)
                        .OrderBy("start/DateTime")
                        .GetAsync();

This can be simplified that further:

var oEvents = await _graphClient
                        .Me
                        .Calendars[oSettings.CalendarID]
                        .Events
                        .Request()
                        .Top(50)
                        .Filter(strFilter)
                        .OrderBy("start/DateTime")
                        .GetAsync();

This resource was very handy. In the end I have:

public async Task<bool> DeleteCalendarEvents(SettingsBase oSettings)
{
    try
    {
        var oEvents = await _graphClient
                                .Me
                                .Calendars[oSettings.CalendarID]
                                .Events
                                .Request()
                                .Select("Start,Subject,Id") // TODO: Is there any point doing this?
                                .Top(50)
                                .Filter(oSettings.GetFilterString())
                                .OrderBy("start/DateTime")
                                .GetAsync();

        List<Event> listEvents = new List<Event>();

        listEvents.AddRange(oEvents);
        while(oEvents.NextPageRequest != null)
        {
            oEvents = await oEvents.NextPageRequest.GetAsync();
            listEvents.AddRange(oEvents);
        }

        foreach(Event oEvent in listEvents)
        { 
            await _graphClient.Me.Events[oEvent.Id].Request().DeleteAsync();
        }

    }
    catch(Exception ex)
    {
        SimpleLog.Log(ex);
        Console.WriteLine("DeleteCalendarEvents: See error log.");
        return false;
    }

    return true;
}