.NET Programmatically accessing Exchange shared and public folders

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DeborahK - 07 Aug 2006 21:54 GMT

I am trying to programmatically access Exchange shared and public folders via
Outlook from a .NET application.

Here is the line of code that is generating an error:

Dim olns As Outlook.NameSpace = OutlookInstance.GetNamespace("MAPI")
mapiFolder = olns.GetFolderFromID(folderID, storeID)

The error is:
"The messaging interface has returned an unknown error. If the problem
persists, restart Outlook".

I don't get the error message when accessing the user's default mailbox. I
also don't get the error message if the user manually opens Outlook before
using my application.

The application is correctly loading Outlook using:
' Create the instance of outlook
_OL = New Outlook.Application
I know this because I can see Outlook being added to the Task Manager.

I have been struggling with this for days so if anyone has ideas I would
appreciate them.

THANKS!

Reply to this Message

Sue Mosher [MVP-Outlook] - 11 Aug 2006 01:57 GMT

If Outlook hasn't been started yet, you can use the Namespace.Logon method to start it with a particular mail profile.

FYI, there is a newsgroup specifically for general Outlook programming issues "down the hall" at microsoft.public.outlook.program_vba or, via web interface, at http://www.microsoft.com/office/community/en-us/default.mspx?dg=microsoft.public
.outlook.program_vba

Signature

Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
http://www.turtleflock.com/olconfig/index.htm
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx

>I am trying to programmatically access Exchange shared and public folders via
> Outlook from a .NET application.
[quoted text clipped - 21 lines]
>
> THANKS!

Reply to this Message

DeborahK - 11 Aug 2006 15:47 GMT

Hi Sue -

Thank you for replying to my question. We tried that with several different
types of parameters (no parameters, all parameters, etc) and that did not
help. It still generates an error on the GetFolderFromID statement.

> If Outlook hasn't been started yet, you can use the Namespace.Logon method to start it with a particular mail profile.
>
[quoted text clipped - 25 lines]
> >
> > THANKS!

Reply to this Message

Sue Mosher [MVP-Outlook] - 11 Aug 2006 22:42 GMT

If Outlook isn't running, you'd want to use either

olns.Logon "profile_name", "", False, True

or possibly

olns.Logon "", "", True, True

This is a standalone Windows application? Check to see whether your anti-virus client has script blocking turned on.

Signature

> Hi Sue -
>
[quoted text clipped - 31 lines]
>> >
>> > THANKS!

Reply to this Message

DeborahK - 16 Aug 2006 23:20 GMT

Hi Sue -

Thanks again for replying. Just wanted you to know that we figured this out.
In case someone else runs into this - here is what we found:

- The storeID is critical to accessing any shared or public folders - but
only the first time in a session. There was one place in the code that was
messing up the store ID. Oddly enough, the store ID does NOT matter in the
following cases:
(1) Outlook has previously been opened.
(2) The user had followed a path in the code that referenced the folder with
a store ID.

But it *does* matter if Outlook has not been opened and this is the first
time accessing the folder.

Once we got the storeID to be correct in all paths of the code - everything
worked fine...

Thanks again for your assistance!

> If Outlook isn't running, you'd want to use either
>
[quoted text clipped - 41 lines]
> >> >
> >> > THANKS!

Reply to this Message