Maintaining Custom Toolbar Positions in Outlook 2007

NOTE: This applies to Visual Studio 2008 and Outlook 2007.

There are a few articles floating around have examples on saving toolbar position information at the end of a session and restoring that position the next time Outlook is loaded. One at MSDN applies to Visual Studio 2008 and .NET Framework 3.5:

How to: Maintain Position Information for Custom Toolbars between Outlook Sessions

I tried this code with Outlook 2007 and it throws an exception on shutdown when it tries to save the toolbar position information. Reading the article again, I noticed that it says it applies to Outlook 2003.

I just assumed that it would work with Outlook 2007, and why would they release an article for Visual Studio 2008 that works with an old version of Outlook?

The exception that is being thrown when the CommandBar instance is accessed is:

System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x800A01A8

Look up this HRESULT value and you can see that it means "Object Required".

To me, this means that the CommandBar has already been cleaned up and is no longer accessible. ThisAddIn_Shutdown is supposedly the first user code to be run before a shutdown occurs, so what do you do?

I have settled on listening to the Close event of the main Explorer window (the one the CommandBar is added to). This is called before ThisAddIn_Shutdown and the CommandBar is still accessible.

Example:

  ...

  private void ThisAddIn_Startup(object sender, System.EventArgs e)
  {
      Outlook.Explorer explorer = this.Application.ActiveExplorer();
    
      if (explorer != null)
      {
          ((ExplorerEvents_10_Event)explorer).Close += new ExplorerEvents_10_CloseEventHandler(ThisAddIn_Close);

          commandBar = explorer.CommandBars.Add(TOOLBARNAME,
              Office.MsoBarPosition.msoBarFloating, false, true);
        
          ...
      }
  }

  private void ThisAddIn_Close()
  {
      SaveCommandBarSettings();
  }

  ...