COM object that has been separated from its underlying RCW cannot be used with Outlook

Question

I have an application which loads email-addresses into a list and uses these for autocompletion in a textbox. If I close my application while these addresses are still being retrieved I get the InvalidComObjectException was unhandled by user code error.

The error is specified on a certain piece of code:

  Outlook.NameSpace oNS = ((Microsoft.Office.Interop.Outlook.Application)OutlookObj).GetNamespace("MAPI");

This is the entire auto-completion class:

     class AutoComplete
{
    List<string> emailList = new List<string>();
    Outlook.Application OutlookObj = new Outlook.Application();
    string[] names;

    public List<string> getEmails()
    {

            Outlook.AddressLists addresslists = OutlookObj.Session.AddressLists;
            Outlook.AddressList gal = addresslists["All Users"];
            Outlook.AddressEntries addrEntries = gal.AddressEntries;
            names = new string[addrEntries.Count];

            for (int i = 1; i < addrEntries.Count; i++)
            {
                Outlook.AddressEntry exchDLMember = addrEntries[i];
                Outlook.NameSpace oNS = ((Microsoft.Office.Interop.Outlook.Application)OutlookObj).GetNamespace("MAPI");
                Outlook.Recipient recip = oNS.CreateRecipient(exchDLMember.Name);
                recip.Resolve();
                if (recip.Address != null && recip.AddressEntry != null)
                {
                    if (recip.AddressEntry.GetExchangeUser().PrimarySmtpAddress != null)
                    {
                        names[i] = recip.AddressEntry.GetExchangeUser().PrimarySmtpAddress;
                    }
                }
            }
            foreach (string combo in names)
            {
                if (combo != null)
                {
                    emailList.Add(combo);
                }
                else { }
            }
            return emailList; 

    }
}

The backgroundWorker methods in the Form:

void Form1_Shown(object sender, EventArgs e)
    {
        bgW.RunWorkerAsync();
        bgW.WorkerSupportsCancellation = true;
    }

    void bgW_DoWork(object sender, DoWorkEventArgs e)
    {
        bgW.WorkerSupportsCancellation = true;
        if(textBox1.InvokeRequired)
        {                
            emails = autoComplete.getEmails();
            collection.AddRange(emails.ToArray());                
            textBox1.Invoke(new MethodInvoker(delegate { textBox1.AutoCompleteCustomSource = collection; }));
        }            

        for (int i = 100; i <= 100; i++)
        {
            bgW.ReportProgress(i);
            if (i == 100)
            {
                label2.Invoke(new MethodInvoker(delegate { label2.Text = "Global Address List Loaded!"; }));
                label2.Invoke(new MethodInvoker(delegate { label2.BackColor = System.Drawing.Color.LightGreen; }));
            }
        }
    }

And upon closing the form:

   private void Form1_FormClosing(Object sender, FormClosingEventArgs e)
    {
        bgW.CancelAsync();         
    }

Anyone have an idea about preventing this error?

It is up to you to ensure that you do not close the form, and thus terminate the thread that owns the Outlook object, and thus trigger this exception, until you are sure that the worker thread finished running and can no longer use the object. The subject of [this Q+A](http://stackoverflow.com/questions/1731384/how-to-stop-backgroundworker-on-forms-closing-event). — Hans Passant, Jan 27 '16 at 15:35
That was an idea that crossed my mind but I was hoping there would be a way to terminate the thread by using the form_formclosing method or some other way. — Alim, Jan 27 '16 at 15:45

score 0 · Accepted Answer · answered Jan 27 '16 at 15:55

0

Hans Passant: Sure, Environment.Exit(). Bam, gone.

Adding Enviroment.Exit(0); to the Form1_FormClosing() like Hans said did the trick everything gets closed when exiting the application now.

answered Jan 27 '16 at 15:55

Alim

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COM object that has been separated from its underlying RCW cannot be used with Outlook

1 Answers1