I am working on a sync client that replicate appointment from and to EWS (Office 365).
In general I am following the documentation provided by MS: https://msdn.microsoft.com/en-us//library/office/dn440952(v=exchg.150).aspx
My problem:
This article https://msdn.microsoft.com/en-us//library/office/dn605828(v=exchg.150).aspx#Arbeiten%20mit%20Bezeichnern shows that the ItemId of a appointment may change and is not unique.
So investigating I found out that people load cleanGlobalObjectId from appointment that is unique once and for all.
// unique id for sync that do not change like item id
var cleanGlobalObjectId = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.Meeting, 0x23, MapiPropertyType.Binary);
var psPropSet = new PropertySet(BasePropertySet.FirstClassProperties) { cleanGlobalObjectId };
So I use
var appointment = Appointment.Bind(service, item, psPropSet);
object calIdVal;
appointment.TryGetProperty(cleanGlobalObjectId, out calIdVal);
var syncId = Convert.ToBase64String((byte[])calIdVal);
syncId is so far I tested unique and works for INSERT and UPDATE appointments into my database.
When I now use SyncFolderItems from EWS I get a collection of items for create,update,delete.
My problem:
I can not load appointments with Appointment.Bind() that are deleted.
But I need to load the appointment to get my syncId.
The SyncFolderItems collection let me access ItemId.UniqueKey and ItemId.ChangeKey.
So if an appointment is moved or deleted in a users calendar I have no chance to identify the correct record in my client database where I save the replicated appointments.
So anyone have some advise or any other approaches? If I forgot to add some details please also provide some feedback so I can add this.
