title: How to sum column value in ClosedXML
body: <p>I have 9 columns and I want to sum value of each column in ClosedXML.</p>
  <p>These are the columns :</p>
  <pre><code>foreach (Attivita attivita in listaSomthing)
  {
       worksheet.Cell(index, 1).Value = attivita.Somthing;
       worksheet.Cell(index, 2).Value = attivita.Somthing;
       worksheet.Cell(index, 3).Value = attivita.Somthing;
       worksheet.Cell(index, 4).Value = attivita.Somthing;
       worksheet.Cell(index, 5).Value = attivita.Somthing;
       worksheet.Cell(index, 6).Value = attivita.Somthing;
       worksheet.Cell(index, 7).Value = attivita.Somthing;
       worksheet.Cell(index, 8).Value = attivita.Somthing;
       worksheet.Cell(index, 9).Value = attivita.Somthing;
   }
  </code></pre>
  <p>I need to sum total of Cell(index, 1), Cell(index, 2)...Cell(index, 9).</p>
  <p>And this is the table:</p>
  <p><a href="https://i.stack.imgur.com/Nij6E.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Nij6E.png" alt="enter image description here" /></a></p>
  <p>I didn't find any useful info in the ClosedXML documentation.</p>
  <p>Can anyone help me, please?</p>
  <p>Thanks in advance!</p>