title: Prevent PHPExcel to calculate values when writing to file
body: <p>When writing my data in an Excel file with class PHPExcel.</p>
  
  <p><strong>This is happening when the writer works, not when adding data to the cells <code>$this-&gt;sheet-&gt;setCellValue()</code></strong></p>
  
  <pre><code>Fatal error: Uncaught exception 'PHPExcel_Calculation_Exception' with message 'Adressen!AF20955 -&gt; Formula Error: Unexpected operator '&gt;'' in \Cell.php:300 Stack trace: 
  #0 \PHPExcel\Worksheet.php(754): PHPExcel_Cell-&gt;getCalculatedValue()
  #1 \PHPExcel\Writer\Excel2007\Worksheet.php(373): PHPExcel_Worksheet-&gt;calculateColumnWidths()
  #2 \PHPExcel\Writer\Excel2007\Worksheet.php(80): PHPExcel_Writer_Excel2007_Worksheet-&gt;_writeCols(Object(PHPExcel_Shared_XMLWriter), Object(PHPExcel_Worksheet))
  #3 \PHPExcel\Writer\Excel2007.php(304): PHPExcel_Writer_Excel2007_Worksheet-&gt;writeWorksheet(Object(PHPExcel_Worksheet), Array, false)
  #4 \excel.php(131): PHPExcel_Writer_Excel2007-&gt;save('...')
  #5 \excel. in \PHPExcel\Cell.php on line 300
  </code></pre>
  
  <p>I never use the function <code>PHPExcel_Cell-&gt;getCalculatedValue()</code> writing to my Excel but only <code>$this-&gt;sheet-&gt;setCellValue('A1', $value)</code>.</p>
  
  <p>I don't need to calculate any formula in my Excel file. Just exporting DB2 data to this file.</p>
  
  <p>It is obviously possible that <code>$value</code> contains formula characters like <code>= + - &gt; &lt;</code> (as the cell <code>AF20955</code> did causing the fatal error with <code>&gt;</code>) but this should not be interpreted as formula but only as part of string. How can I solve the problem?</p>