title: Programmatically modifying a Sharepoint Online Excel file
body: <p>We need to create a c# application that can modify an Excel file in one of our Sharepoint online sites.</p>
  
  <p>For a local file I do like this:</p>
  
  <pre><code>Excel.Application excel_app = new Excel.Application();
  excel_app.Visible = true;
  Excel.Workbook workbook = excel_app.Workbooks.Open(
          &lt;path to excel file&gt;,
          Type.Missing, Type.Missing, Type.Missing, Type.Missing,
          Type.Missing, Type.Missing, Type.Missing, Type.Missing,
          Type.Missing, Type.Missing, Type.Missing, Type.Missing,
          Type.Missing, Type.Missing);
  </code></pre>
  
  <p>But if I put the url of the Sharepoint Excel file it does not work. Is this feasible, and how?</p>