title: PHPExcel how to link a sheet column to a cell using setFormula1()
body: <p>I am using a <code>PHPExcel</code> for xls creation. how can i link a sheet column to a drop down cell. i have created a drop down in xls but how can i get sheet column like whole A column in drop down for drop down values. 
  In excel i have done this manually when i link a sheet column to any cell its making formula like this </p>
  
  <blockquote>
    <p>=DropdownSheet!$A:$A</p>
  </blockquote>
  
  <p><strong>DropdonSheet</strong> is a sheet name <strong>A</strong> is a column that i am linking </p>
  
  <p>I have build a sheet using PHPExcel exactly i have done in excel <code>DropdonSheet</code> when i write this formula in PHPExcel to populate dropdown </p>
  
  <pre><code>$objValidation-&gt;setFormula1("=DropdownSheet!$A:$A");
  </code></pre>
  
  <p>its not working giving me an error. what i am doing wrong can any one please guide me here is my whole code </p>
  
  <pre><code>    $objPHPExcel = new PHPExcel();
  
  // Create a first sheet, representing sales data
  $objPHPExcel-&gt;setActiveSheetIndex(0);
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A1', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A2', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A3', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A4', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A5', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A6', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A7', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A8', 'Something');
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A9', 'Something');
  
  // Rename sheet
  $objPHPExcel-&gt;getActiveSheet()-&gt;setTitle('DropdownSheet');
  
  // Create a new worksheet, after the default sheet
  $objPHPExcel-&gt;createSheet();
  
  // Add some data to the second sheet, resembling some different data types
  $objPHPExcel-&gt;setActiveSheetIndex(1);
  $objPHPExcel-&gt;getActiveSheet()-&gt;setCellValue('A1', 'More data');
  $objValidation = $objPHPExcel-&gt;getActiveSheet()-&gt;getCell("B1")-&gt;getDataValidation();
  $objValidation-&gt;setType( PHPExcel_Cell_DataValidation::TYPE_LIST );
  $objValidation-&gt;setErrorStyle( PHPExcel_Cell_DataValidation::STYLE_INFORMATION );
  $objValidation-&gt;setAllowBlank(false);
  $objValidation-&gt;setShowInputMessage(true);
  $objValidation-&gt;setShowErrorMessage(true);
  $objValidation-&gt;setShowDropDown(true);
  $objValidation-&gt;setErrorTitle('Input error');
  $objValidation-&gt;setError('Value is not in list.');
  $objValidation-&gt;setPromptTitle('Pick from list');
  $objValidation-&gt;setPrompt('Please pick a value from the drop-down list.');
  $objValidation-&gt;setFormula1("=DropdownSheet!$A:$A");
  
  // Rename 2nd sheet
  $objPHPExcel-&gt;getActiveSheet()-&gt;setTitle('Second sheet');
  </code></pre>