title: C# project does not see Excel COM Reference
body: <p>im writing an application using Visual Studio 2010 Express Edition. I have a problem using Excel Automation. I added a COM Reference to Microsoft Excel 12.0 Object Library. It added following References: </p>
  
  <pre><code>Microsoft.Office.Core
  Microsoft.Office.Interop.Excel 
  VBIDE
  </code></pre>
  
  <p>I also added a using clause: </p>
  
  <pre><code>using Microsoft.Office.Interop.Excel;
  </code></pre>
  
  <p>Then i took a code snippet from <a href="http://support.microsoft.com/kb/306023" rel="nofollow">microsoft</a>: </p>
  
  <pre><code>m_objExcel = new Excel.Application();
  m_objBooks = (Excel.Workbooks)m_objExcel.Workbooks;
  m_objBook = (Excel._Workbook)(m_objBooks.Add(m_objOpt));
  </code></pre>
  
  <p>and it underlines Excel and shouts: </p>
  
  <blockquote>
    <p>The type or namespace name 'Excel'
    could not be found (are you missing a
    using directive or an assembly
    reference?)</p>
  </blockquote>
  
  <p>I have Office 2007 Professional Plus and the <em>"Interoperability component for .net 2.0 Microsoft Forms"</em> (sorry, translation from polish) installed. Target Framework is .NET 4 Client Profile.</p>
  
  <p>Any ideas what can be wrong?</p>