/**
  * @param GridField $gridField
  * @param DataObject $record
  * @param string $columnName
  *
  * @return string - the HTML for the column
  */
 public function getColumnContent($gridField, $record, $columnName)
 {
     if (!$record instanceof Member || !$record->canMasquerade()) {
         return;
     }
     // No permission checks, handled through GridFieldDetailForm,
     // which can make the form readonly if no edit permissions are available.
     $data = new ArrayData(array('Link' => Controller::join_links($gridField->Link('item'), $record->ID, 'masquerade')));
     return $data->renderWith('GridFieldMasqueradeButton');
 }