VSTO Outlook Plugin: Cannot get AppointmentItem in Item_Change event when recurring appointment is dragged and dropped by user - vsto

Question

I want to catch the change event on an AppointmentItem. I use Outlook 2017 for tests.
To achieve I use:
I attached the events like this:
public void AttachEvents()
{
_CalendarItems.ItemAdd += Item_Add;
_CalendarItems.ItemChange += Item_Change;
_DeletedItems.ItemAdd += Item_Delete_Add;
The Item_Change method looks like this:
public void Item_Change(Object item)
{
if (item != null && item is Outlook.AppointmentItem)
{
Outlook.AppointmentItem myAppointment = item as Outlook.AppointmentItem;
To test the code I created a recurring appointment series. I double-clicked on appointment in the calendar and entered some title and body and saved.
Now I started my code and inspected the item.
Unfortunately, item points to the series and NOT to the individual appointment when item changed is initiated.
How can I retrieve the actual AppointmentItem when Item_Changed is initiated?
Related Stackoverflow Posting: Outlook Addin: Moving Appointment in Calendar does not reflect new date/time in AppointmentItem (catch Calendar.ItemChange) But still there is no solution to this
More on this topic:
https://www.add-in-express.com/forum/read.php?FID=5&TID=15384
https://social.msdn.microsoft.com/Forums/sqlserver/en-US/4ec55891-fb64-408f-b1cf-4bf05765b866/outlook-get-original-time-of-recurring-exception-item-that-is-opened-with-drag-drop?forum=vsto

Answer 1

Exceptions are not actual appointments - they are stored as embedded message attachments on the master appointments. You get the master appointment, and you would need to access its exceptions to see what changed.

Answer 2

There is a tricky solution to that.
Assumption: The user uses the calendar view to change the item. As the event is thrown by the calendar view this should be true in all cases:
_CalendarItems = calendarFolder.Items;
_CalendarItems.ItemChange += Item_Change;
[...]
now we can use the CalendarView to calculate the selected Startdate and compare it to all Exceptions stored in the RecurrencePattern ...
if (myAppointment.IsRecurring)
{
// in case of recurring appointments at this point we always get
// only a reference to the series master NOT the occurrence
// Assumption: The user clicked on the AppointmentItem in the calendar view
// So we can calculate the selected Start Time from this selection range
// then compare this against all Exceptions in the OccurrencePattern of the recurring pattern
// if we find one AppointmentItem in the Exceptions which has the same DateTime then we found the correct one.
//
Outlook.Application application = new Outlook.Application();
Outlook.Explorer explorer = application.ActiveExplorer();
Outlook.Folder folder = explorer.CurrentFolder as Outlook.Folder;
Outlook.View view = explorer.CurrentView as Outlook.View;
// get the current calendar view
if (view.ViewType == Outlook.OlViewType.olCalendarView)
{
Outlook.CalendarView calView = view as Outlook.CalendarView;
Outlook.RecurrencePattern pattern = myAppointment.GetRecurrencePattern();
for (int i = 1; i <= pattern.Exceptions.Count; i++)
{
Outlook.Exception myException = pattern.Exceptions[i];
Outlook.AppointmentItem exceptionItem = myException.AppointmentItem;
DateTime itemDateStart = exceptionItem.Start;
if (itemDateStart == calView.SelectedStartTime)
{
updateMyPluginMeeting(exceptionItem);
return; // the use may only select on AppointmentItem so we can skip the rest
}
}
}
}
If you know any better solution to this let me know.