PDO不能转换成字符串PHP

问题描述：

通数据库类对象的其他类我得到这个消息“开捕致命错误：类PDO的对象无法被转换成字符串”，同时，代码工作正常，如果我评论此行'//$imageobj= new image($dbobj);'？

更新：一旦我加入这行$this->dbconn=null;到getConnection()功能db.class.php尝试之前{}。每件事情都很好！

index.php

<?php 
include "./classes/db.class.php"; 
include "./classes/image.class.php"; 

$dbobj= new db(); 
$imageobj= new image($dbobj); 

$page_title="Shopping Center !"; 
include './template/header.php'; 

$dbobj->getConnection(); 

include './template/footer.php';

db.class.php

class db { 
    private $host; 
    private $dbname; 
    private $username; 
    private $password; 
    private $dbconn; 
    private $status; 

    public function __construct() { 
     // the require paramaters to start db connnection 
     $this->host = '127.0.0.1'; 
     $this->dbname = 'shop_carta'; 
     $this->username = 'root'; 
     $this->password = ''; 
     $this->status = 0; 
     //$this->dbconn = null; 
    } 

    public function getConnection() { 
     try { 
      $this->dbconn = new PDO("mysql:host=$this->host;dbname=$this->dbconn", $this->username, $this->password); 
      if (!is_null($this->dbconn)) { 

       $this->status = $this->dbconn->getAttribute(PDO::ATTR_CONNECTION_STATUS); 
       $this->dbconn->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); 
       $this->dbconn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

       return $this->dbconn; 
      } else { 
       echo "<div class='alert alert-danger'>" 
       . " Our server Busy Now try again later.. </div></br>"; 
       return false; 
      } 
     } catch (PDOException $ex) { 
       return false; 
     }}}

image.class.php this class receive the $dbobject try to $dbobject->getConncetion() and set retrieve

class image { 
    private $table_name = 'product_images'; 
    private $dbconn; 
    public $id; 
    public $name; 

    public function __construct($dbobj) { 
     $this->dbconn = $dbobj->getConnection(); 
     }}

将dbconn指定为null解决方案： 可捕获的致命错误：类PDO的对象无法转换为字符串。任何建议为什么？

显示图像类的代码 - 似乎image'的'的构造函数只接受字符串，但你传递整个'db'对象 –

class image {0}私人$ table_name ='product_images'; private $ dbconn; public $ id; public $ name;公共函数__construct（$ dbobj）{ $ this-> dbconn = $ dbobj-> getConnection（）; }} – Mvrk

答

问题就出在这里：

"mysql:host=$this->host;dbname=$this->dbconn"

DBNAME应该是一个数据库名称。您提供的属性（在添加$ this-> dbconn = null之前）不存在，这就是您遇到错误的原因。

添加$ this-> dbconn = null，可以防止致命的不存在的属性，但你仍然提供一个空的数据库名称。

你应该用这个 - $> DBNAME取代它，像这样解决这个问题：

"mysql:host=$this->host;dbname=$this->dbname"

这是愚蠢的错误感觉很愚蠢：/。谢谢@Erik。 – Mvrk

PDO不能转换成字符串PHP

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