title: PHPexcel save to CSV linked cells to another sheet are empty
body: <p>Could someone help me?
  I have xlsx file, with 2 sheets.</p>
  
  <p>Second sheet contain cells linked to another(first) sheet.
  When I save sheet to CSV file: </p>
  
  <pre><code>$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'CSV');
  </code></pre>
  
  <p>This function doesn't save (linked) cells value...</p>
  
  <p>My code looking like this:</p>
  
  <pre><code>$objPHPExcel = new PHPExcel();
  
  //  Read your Excel workbook
  try 
  {
      $inputFileType = PHPExcel_IOFactory::identify($excelFile);
      $objReader = PHPExcel_IOFactory::createReader($inputFileType);
      $objReader-&gt;setLoadSheetsOnly('list'); 
      $objReader-&gt;setLoadSheetsOnly('main'); 
      /* I also tried like this: 
      $worksheetList = $objReader-&gt;listWorksheetNames($excelFile);
      $sheetname = $worksheetList[0]; 
      $sheetname2 = $worksheetList[1]; 
      $objReader-&gt;setLoadSheetsOnly($worksheetList[0]); 
      $objReader-&gt;setLoadSheetsOnly($sheetname); 
      */
  $objPHPExcel = $objReader-&gt;load($excelFile);
  }
  
  $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'CSV');
  $objWriter-&gt;save($filename);
  </code></pre>
  
  <p>I also tried to save to EXCEL files (xls and xlsx) -> the same problem, the cells (which was linked) they are empty...</p>
  
  <p>My linked cells looked like this: "=list!C46"</p>
  
  <p>Many hours of looking for answer, I have found not good solution:
  I've removed any of these lines:         <code>$objReader-&gt;setLoadSheetsOnly('list');</code> 
  and add:</p>
  
  <pre><code>$activeSheetData = $objPHPExcel-&gt;getActiveSheet()-&gt;toArray(null, true, true, true);
  $objPHPExcel-&gt;getActiveSheet()-&gt;fromArray($activeSheetData, false);
  </code></pre>
  
  <p>just after:</p>
  
  <p><code>$objPHPExcel = $objReader-&gt;load($excelFile);</code></p>
  
  <p>and also add: <code>$objWriter-&gt;setSheetIndex(1);</code> 
  Now it will works, but with problems...</p>
  
  <p>One column in original format have linked cells like this: <strong>"=list!$AV$46"</strong>
  I mean with $ symbol.</p>
  
  <p>More detailed:
  If I have:   <code>$objReader-&gt;setReadDataOnly(true);</code>
  and have those cells: "=list!$AV$46" then they are empty in output.</p>
  
  <p>But if I remove: <code>$objReader-&gt;setReadDataOnly(true);</code>
  then those cells: "=list!$AV$46" works good and have a value, but with format
  like: 11/17/2017.
  <br>As I removed <code>$objReader-&gt;setReadDataOnly(true);</code>, then I can't apply
  this my code:
  <code>$objPHPExcel-&gt;setActiveSheetIndex(1)-&gt;getStyle('AV1:AV'.$highestRow)-&gt;getNumberFormat()-&gt;setFormatCode(PHPExcel_Style_NumberFormat::FORMAT_DATE_YYYYMMDD);</code></p>
  
  <p>Then second question, how to write new date format?
  I also wanted to say, that initial date format was:
  17.11.2017. 
  And I wanted 17-11-17 (FORMAT_DATE_YYYYMMDD).</p>
  
  <p>And again, with cells which looks like <code>"=list!AV46"</code> all works good.</p>
  
  <p><strong>UPDATE:</strong> Solvation: <code>$objReader-&gt;setLoadSheetsOnly(['list', 'main']);</code> + <code>$objPHPExcel-&gt;setActiveSheetIndex(1);</code> before any of: <code>$objPHPExcel-&gt;getActiveSheet()-&gt;...</code></p>