必须在zend2中返回一个字符串值。怎么样？

Question

我有一个zend2形式的问题。我做了从数据库中获取一些数据，并加入一些表实体...

这里是实体：

class Campaigns 
{ 
    /** 
    * @ORM\Id 
    * @ORM\GeneratedValue(strategy="AUTO") 
    * @ORM\Column(type="integer") 
    */ 
    protected $id; 

    /** 
    * 
    * @ORM\Column(name="campaign_name", type="string") 
    * 
    */ 
    protected $campaigns; 

    /** 
    * @var mixed 
    * 
    * @ORM\ManyToMany(targetEntity="Application\Entity\Countries", cascade={"persist"}, orphanRemoval=false) 
    * @ORM\JoinTable(name="campaigns_countries", 
    *  joinColumns={@ORM\JoinColumn(name="campaign_id", referencedColumnName="id", onDelete="CASCADE")}, 
    *  inverseJoinColumns={@ORM\JoinColumn(name="country_id", referencedColumnName="id", onDelete="CASCADE")} 
    *  ) 
    */ 
    protected $countries; 

下面这段代码是getter和setter，一个构造函数，附加和一个删除功能。

在这里，他们是：

public function getId() 
    { 
     return $this->id; 
    } 

    public function setId($id) 
    { 
     $this->id = $id; 
     return $this; 
    } 

    public function getCampaigns() 
    { 
     return $this->campaigns; 
    } 

    public function setCampaigns($campaigns) 
    { 
     $this->campaigns = $campaigns; 
     return $this; 
    } 



    public function addCampaigns($campaigns = null) 
    { 
     foreach ($campaigns as $c) { 
      if (!$this->campaigns->contains($c)) { 
       $this->campaigns->add($c); 
      } 
     } 
    } 

    public function removeCampaigns($campaigns) 
    { 
     foreach ($campaigns as $c) { 
      if ($this->campaigns->contains($c)) { 
       $this->campaigns->removeElement($c); 
      } 
     } 
    } 
    public function getCountries() 
    { 
     return $this->countries; 
    } 

    public function setCountries($countries) 
    { 
     $this->countries = $countries; 
     return $this; 
    } 

    public function addCountries($countries = null) 
    { 
     foreach ($countries as $c) { 
      if (!$this->countries->contains($c)) { 
       $this->countries->add($c); 
      } 
     } 
    } 

    public function removeCountries($countries) 
    { 
     foreach ($countries as $c) { 
      if ($this->countries->contains($c)) { 
       $this->countries->removeElement($c); 
      } 
     } 
    } //construct for countries 
    public function __construct() 
    { 
     $this->setCountries(new ArrayCollection()); 
    } 

我的问题是与protected $countries。如果我在表单中添加属性值，它会给我在实体中找不到的“国家/地区”属性。

如果我不加它，而是使用__toString()功能，它给了我一个错误说，它不能转换的国家串......在__toString()函数添加以下代码：

public function __toString() 
{ 

return $this->countries; 

} 

谢谢你的帮助！

AE

Answer 1

你说你想要一个包含所有相关国家的字符串。以下代码演示如何实现此目的：

$campaignCountryNames = array(); 

$campaignCountries = $campaign->getCountries(); 

foreach ($campaignCountries as $country) { 
    // I assume your Country entity has a name property 
    $campaignCountryNames[] = $country->getName(); 
} 

echo implode(', ', $campaignCountryNames);