title: Trying to add multiple sheets to excel
body: <p>i'm trying to programmatically add sheets to a new excel document.</p>
  
  <p>my expected output is sheets named 'test1-20' but instead i get 'Sheet1-19, test20'.</p>
  
  <p>why doesn't this work?</p>
  
  <pre><code>Workbook workbook;
  Application objExcel;
  
  objExcel = new Application();
  objExcel.Visible = false;
  objExcel.DisplayAlerts = false;
  
  for (var i = 0; i &lt; worksheets.Count; i++)
  {
      workbook= objExcel.Workbooks.Add(Missing.Value);
      var worksheet = (Worksheet)workbook.Worksheets.get_Item(i + 1);
      worksheet.Name = string.Format("test{0}", i + 1);
  }
  </code></pre>