title: Apply percentage format with VSTO - multiply by 100 behind the scenes
body: <p>I have a piece of code that formats cell according to requirements:</p>
  
  <pre><code>        Range.Font.Italic = Microsoft.Office.Core.MsoTriState.msoTrue;
          Range.HorizontalAlignment = XlHAlign.xlHAlignGeneral;
          Range.NumberFormat = "0.0_%_);(0.0)_%;-_%_)";
  </code></pre>
  
  <p>And this code is invoked then button on custom ribbon is pressed. It's similar to percentage cell format. One more thing I have to add is multiplying the cell value by 100.
  For instance</p>
  
  <ul>
  <li>cell value is set to 0.15, I click button and value changes to 15%.</li>
  <li>cell value is set to 2.5, I click button and value changes to 250% etc. (very similar to default Excel Precentage cell style)</li>
  </ul>
  
  <p>However, if I do something like this:</p>
  
  <pre><code>        decimal result = Convert.ToDecimal(cell.Value);
          cell.Value = result * 100;
  </code></pre>
  
  <p>and user hits button multiple times, value is multiplied every time. Is there a way to specify something like display format, so that actual value is preserved and only displayed value is multiplied by 100? Or another way to prevent value from being multiplied multiple times?</p>