Why does Attendee ResponseType always return Unkown?


  • I am using EWS managed API to fetch a user's calendar items. I see that the ResponseType of all RequiredAttendees in a meeting is of type Unknown, even though I know that all attendees have accepted.

     Is this a known issue. Do I have to do something other than seeing Attendee.ResponseType?



    Thursday, July 08, 2010 12:24 AM

All replies

  • We are having a similar problem.  If the user responds to the meeting event using an iPhone or iPad, we are getting a responseType of "unknown".  Does anyone know of the reason behind this?
    Tuesday, September 06, 2011 5:32 AM
  • We are also experiencing the same behavior, but its not limited to iPhone or iPad.  We are using the managed API (1.1 version) to talk to Exchange Web Services.

    When accepting an invite via OWA or Outlook, I can retrieve the ResponseType of "Accepted" correctly for a user account.  If I accept that invitation from a Windows Phone 7, iPhone or iPad a couple things happen:

    1. If I have Outlook open and I'm looking at the invite in my Inbox, then I accept the invite via my iPhone - the invite is removed from my Inbox and placed on the calendar correctly.  If I open the meeting in Outlook, I can see that it was accepted at the exact time that the iPhone accepted it.

    2. When stepping through the code and I get the list of required attendees, I look at the ResponseType and it gets set to "Unknown"

    3. Open Outlook, open the invite ( I can still see that I've already accepted it and the DTTM ), I Accept the invite and the ResponseType now shows "Accept"

    There have been several RollUp fixes to the exchange server since the last release of the EWS Managed API on November 15th(  Perhaps its fixed on the EWS side and the Managed API needs to catchup to resolve the "unknown" responseType?




    Tuesday, September 06, 2011 10:09 PM
  • Ok, further working through the problem using EWSEditor and some tools that Glen Scales pointed me towards it looks like the issue is only with the Calendar Item's AttendeeCollection.


    Bob creates an invite for Larry and Curly

    Curly Accepts from his via iPhone or Windows Phone

    • Open EWSEditor and connect to Bob's mailbox->Open all items in Calendar->Find my Calendar item and look at the Microsoft.Exchange.WebServices.Data.AttendeeCollection,  and Curly has a responseType of "Unknown".
    • Open EWSEditor and connect to Bob's mailbox->Open all items in the Inbox->Find the "Accepted" message and look at the Microsoft.Exchange.WebServices.Data.MeetingResponseType and it has a value of "Accept" 

    So there are 2 different methods to get the "Accept", one is thru Microsoft.Exchange.WebServices.Data.AttendeeCollection and the other is thru Microsoft.Exchange.WebServices.Data.MeetingResponseType.  While the ResponseType is showing properly in the accepted message, the AttendeeCollection isn't getting updated when someone accepts on anything except Outlook.  

    Perhaps its ActiveSync?  If so, how do I begin to troubleshoot that?



    Friday, September 16, 2011 1:07 AM