CSV 文件未以 cakephp 格式下载

我是cakephp框架的新手。我想生成csv文件。这里我有这样的结果数组：

Array
(
[0] => Array
    (
        [User] => Array
            (
                [username] => yerica
                [email] => amoreyerica@gmail.com
                [phone] => 993643636
            )
        [DealPurchase] => Array
            (
                [deal_title] => Tour de Zaragoza
                [original_price] => 30
            )
    )
[1] => Array
    (
        [User] => Array
            (
                [username] => Rama Test
                [email] => rama@gmail.com
                [phone] => 9652369854
            )
        [DealPurchase] => Array
            (
                [deal_title] => Tour de Zaragoza
                [original_price] => 30
            )
    )
)

在这里，我想生成这个数组的 csv。

在这里，我在视图/助手文件夹中包含 CsvHelper.php 文件。此文件包含：

 <?php
  class CsvHelper extends AppHelper
  {
     var $delimiter = ',';
     var $enclosure = '"';
     var $filename = 'Export.csv';
     var $line = array();
     var $buffer;
     function CsvHelper()
     {
        $this->clear();
     }
     function clear() 
     {
        $this->line = array();
        $this->buffer = fopen('php://temp/maxmemory:'. (5*1024*1024), 'r+');
     }
     function addField($value) 
     {
        $this->line[] = $value;
     }
     function endRow() 
     {
        $this->addRow($this->line);
        $this->line = array();
     }
     function addRow($row) 
     {
       fputcsv($this->buffer, $row, $this->delimiter, $this->enclosure);
     }
     function renderHeaders() 
     {
        header('Content-Type: text/csv');
        header("Content-type:application/vnd.ms-excel");
        header("Content-disposition:attachment;filename=".$this->filename);
     }
     function setFilename($filename) 
     {
        $this->filename = $filename;
        if (strtolower(substr($this->filename, -4)) != '.csv') 
        {
            $this->filename .= '.csv';
        }
     }
     function render($outputHeaders = true, $to_encoding = null, $from_encoding ="auto") 
    {
      if ($outputHeaders) 
      {
        if (is_string($outputHeaders)) 
        {
           $this->setFilename($outputHeaders);
        }
        $this->renderHeaders();
      }
      rewind($this->buffer);
      $output = stream_get_contents($this->buffer);
     if ($to_encoding) 
     {
       $output = mb_convert_encoding($output, $to_encoding, $from_encoding);
     }
     return $this->output($output);
   }
}
?>

在商家控制器（控制器）函数中看起来像：

function download_csv($deal_id)
{           
    $options=array('fields'=>'User.username,User.email,User.phone,DealPurchase.deal_title,DealPurchase.original_price',
                    'joins' =>
                              array(
                                array(
                                    'table' => 'deal_purchases',
                                    'alias' => 'DealPurchase',
                                    'type' => 'inner',
                                    'foreignKey' => false,
                                    'conditions'=> array('DealPurchase.user_id = User.id')
                                )));
          $this->recursive = -1;
          $data = $this->User->find('all', $options);
         $this->set("users",$data);
         $this->layout = null;
         $this->autoLayout = false;
         Configure::write('debug', '0');
    }

在这里，我的视图文件代码是：

<?php
$line= $users[0]['User'];
$this->CSV->addRow(array_keys($line));
foreach ($users as $user)
{
   $line = $user['User'];
   $this->CSV->addRow($line);
}
$filename='users';
echo  $this->CSV->render($filename);

在这里，我的另一个包含下载csv文件和函数链接的功能如下所示：

function deal_list(){            
        $this->_checkMerchantSession();
        $this->set('title_for_layout', 'Deal List');
        $this->layout = "after_login";
        //echo $this->Session->read('userData.Merchant.id');
        //$conditions = "Deal.merchant_id ='".$this->Session->read('userData.Merchant.id')."' AND Deal.isdeleted ='0' AND Deal.isapproved ='0' ";
        $conditions = "Deal.merchant_id ='".$this->Session->read('userData.Merchant.id')."' AND Deal.isdeleted ='0' ";
        //$ArDealdetails = $this->Deal->find('all', array('conditions'=>$conditions,'order'=>'Deal.modified DESC'));
        $this->paginate = array('conditions' => $conditions,'limit' =>5,'order'=>'Deal.id DESC');
        $ArDealdetails = $this->paginate('Deal');
        $this->set('ArDealdetails',$ArDealdetails);    
        $condition1 = "Merchant.id ='".$this->Session->read('userData.Merchant.id')."'";
        $merchant_detail = $this->Merchant->find('first',array('conditions'=>$condition1)); 
        $this->set('merchant_detail',$merchant_detail);        
    }

现在，当我将助手作为 csv 包含时，如下所示：

var $helpers = array('Html', 'Form','Javascript','Fck','Js','Paginator','Csv');

然后它会给出一个错误。那么我该如何解决这个问题呢？

注意：我有一个错误，例如：错误：在此服务器上找不到请求的地址"/商家/deal_list"。我在视图文件中添加了下载 csv 链接deal_list。当我从帮助程序中删除 Csv 时，将显示此页面。

错误：未定义的属性：查看：：$Csv。