title: Microsoft.Office.Interop.Excel.ApplicationClass has no constructor defined
body: <p>I tried to follow <a href="http://csharp.net-informations.com/excel/csharp-open-excel.htm">How to open an Excel file in C# </a> tutorial, i.e. added a reference on the <code>Com</code> tab to <code>Microsoft Office 14.0 Object Library</code> and tried to compile code:</p>
  
  <pre><code>using Excel = Microsoft.Office.Interop.Excel;
  //...
  Excel.Application xlApp;
  Excel.Workbook xlWorkBook;
  Excel.Worksheet xlWorkSheet;
  
  xlApp = new Excel.ApplicationClass();//error here
  //...
  </code></pre>
  
  <p>and faced a compile-time error, saying </p>
  
  <blockquote>
    <p>There is no constructor defined for
    Microsoft.Office.Interop.Excel.ApplicationClass type.</p>
  </blockquote>
  
  <p>What am I missing?</p>