How to Accept and add Categories to RequiredAttendees Appointments using Exchange Web Services - vb.net

Question

I’m using ExchangeService(ExchangeVersion.Exchange2010_SP1)
I want to Accept and add Categories to RequiredAttendees Appointments. To do this i need to find these Appointments.
My understanding in EWS is that on Save of an Appointment that has RequiredAttendees a new Meeting Request is created for each of the ‘required attendees’.
How can I access the Appointments that were created automatically for the ‘required attendees’? These are shown in the required attendees Calendars as Appointments, along with a Meeting Request.
I have managed to do a crude find on the Subject (steps below)
Connect to server as Organiser
Create Appointment
Set Subject
Add Required Attendee
Save Appointment
Connect to server as Required Attendee from step 4
Find Appointment that has Subject at step 3
Add Categories to Appointment at step 7
Update Appointment at step 7
Accept Appointment at step 7
And this does work, but concerned users will change the Subject.
I have tried adding an Extended Property and value to the Appointment created by the Organiser and then FindItems for the Extended Property value in the Appointments connected as the Required Attendee. This does not work.
Is there a preferred method for what I’m trying to accomplish?
Thank you
Private Shared ReadOnly m_organiserEmailAddress As String = "Organiser#test.com"
Private Shared ReadOnly m_eventIdExtendedPropertyDefinition As New ExtendedPropertyDefinition(DefaultExtendedPropertySet.Meeting, "EventId", MapiPropertyType.Long)
'--> start here
Public Shared Function SaveToOutlookCalendar(eventCalendarItem As EventCalendarItem) As String
If eventCalendarItem.Id Is Nothing Then
'new
Dim newAppointment = EventCalendarItemMapper.SaveNewAppointment(eventCalendarItem)
'set the Id
eventCalendarItem.Id = newAppointment.Id.UniqueId.ToString()
'accept the calendar item on behalf of the Attendee
EventCalendarItemMapper.AcceptAppointmentAsAttendees(newAppointment)
Return eventCalendarItem.Id
Else
'update existing appointment
Return EventCalendarItemMapper.UpdateAppointment(eventCalendarItem)
End If
End Function
Private Shared Sub ConnectToServer(Optional autoUser As String = "")
If autoUser = "" Then
_service.Url = New Uri(ExchangeWebServicesUrl)
Else
_service.AutodiscoverUrl(autoUser)
End If
End Sub
Private Shared Sub ImpersonateUser(userEmail As String)
_service.Credentials = New NetworkCredential(ImpersonatorUsername, ImpersonatorPassword, Domain)
_service.ImpersonatedUserId = New ImpersonatedUserId(ConnectingIdType.SmtpAddress, userEmail)
End Sub
Private Shared Function SaveNewAppointment(eventCalendarItem As EventCalendarItem) As Appointment
Try
ConnectToServer(m_organiserEmailAddress)
ImpersonateUser(m_organiserEmailAddress)
Dim appointment As New Appointment(_service) With {
.Subject = eventCalendarItem.Subject}
'add attendees
For Each attendee In eventCalendarItem.Attendees
appointment.RequiredAttendees.Add(attendee.Email)
Next
'add categories
For Each category In eventCalendarItem.Categories
appointment.Categories.Add(Globals.GetEnumDescription(category))
Next
'add EventId = 5059 as an extended property of the appointment
appointment.SetExtendedProperty(m_eventIdExtendedPropertyDefinition, 5059)
appointment.Save(SendInvitationsMode.SendOnlyToAll)
Return appointment
Catch
Throw New Exception("Can't save appointment")
End Try
End Function
Private Shared Sub AcceptAppointmentAsAttendees(appointment As Appointment)
For Each attendee In appointment.RequiredAttendees
Try
ConnectToServer(attendee.Address.ToString())
ImpersonateUser(attendee.Address.ToString())
For Each a In FindRelatedAppiontments(appointment)
a.Categories.Add(Globals.GetEnumDescription(CalendarItemCategory.Workshop))
a.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendToNone)
a.Accept(True)
Next
Catch
Throw
End Try
Next
End Sub
Private Shared Function FindRelatedAppiontments(appointment As Appointment) As List(Of Appointment)
Dim view As New ItemView(1000)
Dim foundAppointments As New List(Of Appointment)
view.PropertySet =
New PropertySet(New PropertyDefinitionBase() {m_eventIdExtendedPropertyDefinition})
'Extended Property value = 5059
Dim searchFilter = New SearchFilter.IsEqualTo(m_eventIdExtendedPropertyDefinition, 5059)
For Each a In _service.FindItems(WellKnownFolderName.Calendar, searchFilter, view)
If a.ExtendedProperties.Count > 0 Then
foundAppointments.Add(appointment.Bind(_service, CType(a.Id, ItemId)))
End If
Next
Return foundAppointments
End Function

Answer 1

Well one thing is for sure that there is nothing straight forward in the EWS.
I will be honest with that, that till the moment, I did not work with integrating from the interior calendar to the Exchange calendar, my experience is the opposite , which is get what in the exchange to the internal one.
Anyway after reading your code, I think you are almost there. However I suggest that you catch the appointments that reach to the attendee by using the Streaming Notifications it is not that hard!
So I would say the steps should be like this
Create the appointment
Apply The extended property thing ( I suggest to use the GUID instead of hard coded number) as follows
Create an extended property, and put guid for the appointment, and it wont change unless you made a copy from another appointment (after all it is just a property)
private static readonly PropertyDefinitionBase AppointementIdPropertyDefinition = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.PublicStrings, "AppointmentID", MapiPropertyType.String);
public static PropertySet PropertySet = new PropertySet(BasePropertySet.FirstClassProperties, AppointementIdPropertyDefinition);
//Setting the property for the appointment
public static void SetGuidForAppointement(Appointment appointment)
{
try
{
appointment.SetExtendedProperty((ExtendedPropertyDefinition)AppointementIdPropertyDefinition, Guid.NewGuid().ToString());
appointment.Update(ConflictResolutionMode.AlwaysOverwrite, SendInvitationsOrCancellationsMode.SendToNone);
}
catch (Exception ex)
{
// logging the exception
}
}
//Getting the property for the appointment
public static string GetGuidForAppointement(Appointment appointment)
{
var result = "";
try
{
appointment.Load(PropertySet);
foreach (var extendedProperty in appointment.ExtendedProperties)
{
if (extendedProperty.PropertyDefinition.Name == "AppointmentID")
{
result = extendedProperty.Value.ToString();
}
}
}
catch (Exception ex)
{
// logging the exception
}
return result;
}
Catch the appointment with the StreamingNotificationEvent. In my opinion a good way to do that is to run both Organizer and Attendee in the same time and catch the appointments between them.
To see an example, I have posted an answer to a previous question Multiple impersonation-threads in Exchange Web Service (EWS) . Please vote for the answers of both posts (here and there) if you found my answers are useful.
I do not want to make you scared, but once you solve your current problem; if you want to continue with it will get more complicated. I could write down how I solved the meetings problem, but I do not see it straight forward at all so it might be better if you write your own.
Cheers