WCF Callback problem when used within add-in

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WCF Callback problem when used within add-in
 
Daniel Rail




Posts: 14
 Joined: 2008-10-03
Hi,

I'm currently using Add-In-Express for Office and .Net 2010, with VS 2008 and .Net 3.5 SP1.

I'm trying to develop a data update notification between applications(stand-alone applications and Outlook add-ins on the network).

I'm trying to implement a WCF callback in my Outlook add-in, but the WCF callback doesn't trigger. And I know that it can connect to the WCF service, because it can send out the data update notification and that the stand-alone application is receiving it, via the WCF callback.

I'm just wondering if there is something that I'm missing for the WCF callback to work in the Outlook add-in. If someone already implemented WCF callbacks in an Outlook add-in, any help would be appreciated.
Posted 22 Jul, 2010 15:34:32 Top
Andrei Smolin


Add-in Express team


Posts: 18830
 Joined: 2006-05-11
Hi Daniel,

There's no such sample available. Talking about principles, it looks more correct to communicate with the service in a standalone application and to let the application to talk to the add-in via the following code path:

OutlookApp.COMAddins.Item(strMyComAddinProgId).Object.MyPublicPropertyOrMethod.

1. strMyComAddinProgId - see the ProgId attribute of your add-in module.
2. MyPublicPropertyOrMethod is called via late binding; see System.Type.InvokeMember in MSDN or seacrh trough this forum.

What do you think?


Andrei Smolin
Add-in Express Team Leader
Posted 23 Jul, 2010 07:42:08 Top
Daniel Rail




Posts: 14
 Joined: 2008-10-03
I'll give it a try.

But, I also need that my add-in can update the Outlook contacts automatically, even if the stand-alone application is not running, since this is a multi-user application.

I'm currently trying to update the contacts using a timer. But, I'm encountering some problems. I'm getting the error: "COM object that has been separated from its underlying RCW cannot be used."

Top of callstack:
System.Runtime.InteropServices.InvalidComObjectException: COM object that has been separated from its underlying RCW cannot be used.
at Microsoft.Office.Interop.Outlook.MAPIFolder.get_Items()
at LexPractica.MSOfficeAddins.AddinModule.LoadContacts() in C:\Users\Daniel Rail\Documents\Visual Studio 2008\Projects\AccraLaw\LexPractica.MSOfficeAddins\AddinModule.cs:line 1030

Here the code that starts at line 1030 in AddinModule.cs: 

foreach (ContactItem vContactItem in LexPracticaContacts.Items)
            {
                DateTime vDateTime = (DateTime)vContactItem.UserProperties["LexPracticaLastSync"].Value;
                if (vDateTime != null)
                {
                    if (vDateTime > vLastSyncTimestamp)
                    {
                        vLastSyncTimestamp = vDateTime;
                    }
                }
            }


The foreach line is line 1030.

Any ideas how I can correct this error?
Posted 23 Jul, 2010 09:33:41 Top
Andrei Smolin


Add-in Express team


Posts: 18830
 Joined: 2006-05-11
Hi Daniel,

"COM object that has been separated from its underlying RCW" means the COM object is released while the .NET object is still alive. I cannot tell you why this occurs because the code above doesn't allow this.

Please read http://www.add-in-express.com/creating-addins-blog/2008/10/30/releasing-office-objects-net/.

In the code above you should use "for" instead of "foreach" and release a number of COM objects. Also, you must not release COM objects supplied to you in parameters of Add-in Express events.


Andrei Smolin
Add-in Express Team Leader
Posted 23 Jul, 2010 10:37:51 Top
Daniel Rail




Posts: 14
 Joined: 2008-10-03
Hi,

The error that I was having was that I was referencing a variable that I assigned on startup that was supposed to contain a reference to the folder. But, obviously that seems to be something that I can't do. And, the RCW error disappeared when I dynamically lookup the folder and assigned it to a local variable, within the method. This permitted me to refresh the contacts using a timer.

But, I wasn't able to get your first suggestion working. I never used late binding before and I can't find a good example to see what I might be doing wrong. If you have a code sample it would be appreciated.
Posted 26 Jul, 2010 07:20:04 Top
Andrei Smolin


Add-in Express team


Posts: 18830
 Joined: 2006-05-11
Hi Daniel,

Please look at http://www.add-in-express.com/creating-addins-blog/2010/03/16/interop-assemblies-late-binding/ and http://www.add-in-express.com/forum/read.php?FID=5&TID=805&MID=3836#message3836. In the latter thread, late binding is used to get the HTMLBody property introduced in Outlook 2002 when using version-neutral interops (Outlook 2000 in this case).


Andrei Smolin
Add-in Express Team Leader
Posted 26 Jul, 2010 08:17:58 Top