Office C# code behin : CommandBar Class Problem ?

[cybertof]

Hello,

Could you please tell me what's wrong with this code
(c# office code behind) :
protected void ThisWorkbook_Open()
{
try
{
MessageBox.Show(ThisApplication.CommandBars.ToStri ng());
MessageBox.Show(ThisApplication.CommandBars.Count. ToString());
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}

The first MessageBox works well and says
'Microsoft.Office.Core.CommandBarsClass'

But the 2nd MessageBox fails in
'Object Reference not set to an instance of an Object'
How to get number of command bars ?
Note :
When you create a new 'Excel C#' project,
is it normal that the wizard ommits the 'office' reference
(which include the Microsoft.Office.Core namespace...)

Thanks for your help.

Cybertof.

[cybertof]

I have 2 'office' Primary Interop assemblies
office v7.0.3300.0 (c:\windows\Microsoft.NET\Framework\v1.1.4322
\office.dll
and

Microsoft Office 11.0 Object Library
c:\windows\assembly\GAC\Office\11.0.0.0__7.......\ office.dll

I have reinstalled Office 2003 and now it works when i start a new
'Excel' project.

But, how can i add manually to an existing 'excel' project the good
assembly ?

Thanks.