EWS错误：超过了1000个项目的最大数量，可以在一个请求中将其删除

Question

我正在使用EWS Exchange Sync，在我的一种方法中，这就是说我超出了可以在单个请求中删除的1000个项目的最大数量。是否可以解决此问题，而不是从日历中删除所有内容，而只从今天起删除，而不是及时删除？导致错误的方法在这里：        public void DeleteAllSafeAppointments(SCDriftConnection conn, ExchangeService service, SAFEAgent agent) {        if(conn == null)            throw new ArgumentNullException("conn");        if(service == null)            throw new ArgumentNullException("service");        if(agent == null)            throw new ArgumentNullException("agent");        try {            var calendar = GetAgentCalendar(service, agent);            service.DeleteItems(GetAllSafeAppointments(calendar).Select(a => a.Id), DeleteMode.HardDelete, SendCancellationsMode.SendToNone, null);            var scheduledActivitiesOnAgent = ScheduledActivity.GetScheduleToExchange(new QueryParameters<ScheduledActivity>(s => s.Initials == agent.Initials && s.ExchangeId != null));            foreach(var schedAct in scheduledActivitiesOnAgent) {                schedAct.ExchangeId = null;                schedAct.Save(conn);            }            ResetAgentSyncState(calendar, agent);        } catch(Exception ex) {            throw new Exception("An error occured while clearing exchange calendar for " + agent.Initials, ex);        }        agent.ExchangeSyncronizationSettings.LastSync = DateTime.Now;        agent.ExchangeSyncronizationSettings.Save(conn);    }

Answer 1

private IEnumerable<Appointment> GetAllSafeAppointments(Folder calendar) {

            ItemView view = new ItemView(512);

            view.PropertySet = new PropertySet(BasePropertySet.IdOnly);

            SearchFilter filter = new SearchFilter.SearchFilterCollection(LogicalOperator.And,

                                                                          new SearchFilter.IsEqualTo(SafeAppointmentFlag, true));

            while(true) {

                var results = SendExchangeRequest(() => calendar.FindItems(filter, view));

                foreach(var r in results.OfType<Appointment>())

                    yield return r;

                if(!results.MoreAvailable)

                    break;

                view.Offset = results.NextPageOffset.Value;

            }

        }

Answer 2

您可以批量处理请求。我为此编写了一个通用批处理方法：

private IEnumerable<IEnumerable<T>> Batch<T>(IEnumerable<T> input, int batchSize)

{

    List<T> items = new List<T>();

    foreach (var item in input)

    {

        items.Add(item);

        if (items.Count == batchSize)

        {

            yield return items;

            items = new List<T>();

        }

    }

    if (items.Count > 0)

    {

        yield return items;

    }

}

现在，您可以使用它将您的物品分成几批：

var batches = Batch(GetAllSafeAppointments(calendar).Select(a => a.Id), 1000);

foreach (var batch in batches)

{

    service.DeleteItems(batch, DeleteMode.HardDelete, SendCancellationsMode.SendToNone, null);

}

现在最多一次将删除1000个。