title: Trouble in Excel.Workbook.SaveAs
body: <p>When I save an excel workbook :</p>
  
  <pre><code>xlWorkbook.SaveAs("C:\\output\\excelfile.xls", Excel.XlFileFormat.xlCSV, 
    misValue, misValue, false, false, Excel.XlSaveAsAccessMode.xlNoChange, 
    misValue, misValue, misValue, misValue, misValue);
  </code></pre>
  
  <p>it have no proplem.</p>
  
  <p>But</p>
  
  <pre><code>String str = "C:\\output\\excelfile.xls";// or get file path from saveFileDialog
  xlWorkbook.SaveAs(str, Excel.XlFileFormat.xlCSV,
    misValue, misValue, false, false, Excel.XlSaveAsAccessMode.xlNoChange,
    misValue, misValue, misValue, misValue, misValue);
  </code></pre>
  
  <p>I found "comexception was unhandled cannot access *.xls",
  why is that?</p>
  
  <p><img src="https://i.stack.imgur.com/Gw9KW.png" alt="enter image description here"></p>