"COM object that has been separated from its underlying RCW cannot be used" exception

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.NET2.0

Hello Everybody.

I have strange situation in my applicaion (MS Outlook Addin).

I work with MailItem object in Item.Open event handler.
I get Inspector object calling MailItem.GetInspector property.
When I try to set handler for Inspector.Close event InvalidComObjectException with message "COM object that has been separated from its underlying RCW cannot be used" is thrown.

Code snippet:

MailItem mailItem;
...
InspectorEvents_10_Event inspectorEvents = mailItem.GetInspector;
inspectorEvents.Close += delegate {.....}; //Exception occurs

In my opinion, it is impossible situation. There is no any call of Marshal.ReleaseComObject between getting Inspector and using it.

This error is reproduced very rarely, so I can't catch it while debugging.

Any suggestions?

Posted 1-Feb-11 7:44am

ielsky

Updated 2-Jan-17 19:50pm

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3 solutions

Solution 3

You need have strong reference to event.
Anything like this

C#

MailItem mailItem;
CloseEvent closeEvent;
...
InspectorEvents_10_Event inspectorEvents = mailItem.GetInspector;
closeEvent = inspectorEvents.Close;
closeEvent += delegate {.....};

Posted 25-May-16 5:45am

Sergey Aseev

Solution 4

hey,

Hi, I am facing the same problem it is really difficult to debug it because the test case is not unique. did you find a solution? I really appreciate your help in advance.Here is my mailbox:1424870395@qq.com

Posted 2-Jan-17 19:50pm

Jason_Kiscy

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Nish Nishant · Accepted Answer · 2011-02-01T07:55:00

Solution 1

One likely cause is that you are accessing a single threaded COM object from different threads. In your case, the event handler may not be running on the thread that created the COM object.

Posted 1-Feb-11 7:55am

Nish Nishant

Comments

ielsky 2-Feb-11 12:52pm

Thank you for you answer.

I checked application log. Thread id in the place where error occurs is the same as thread id in NewInspector handler (where we get Inspector). So, I need another idea.

ncc01 12-Feb-11 3:09am

Hi, I am facing the same problem it is really difficult to debug it because the test case is not unique. did you find a solution? I really appreciate your help in advance.

"COM object that has been separated from its underlying RCW cannot be used" exception

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"COM object that has been separated from its underlying RCW cannot be used" exception

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