PDO在其他类中有什么问题？ [英] What's wrong with PDO in other class?

问题描述

我只是将网站的MySQL更改为PDO，当我尝试在其他类中使用PDO时，我遇到了一个奇怪的问题。

  class Database {
 private $ pdo; 
 
 public function __construct（）{
 $ this-> pdo = new PDO（'mysql：host = localhost; dbname = appdora; charset = utf8'，'root'，'root '）; 
} 
} 
 
 class doClass {
 
 //变量
 private $ db; 
 
 // PDO 
 public function __construct（Database $ db）{
 $ this-> db = $ db; 
} 
  

并且代码返回：以下错误：

Catchable致命错误：传递给doClass :: __ construct（）的参数1必须是Database的实例，无给定，在... / index.php中调用on行xx并在第xx行上的../classes.php中定义

代码：

  $ do = new doClass（）; 
 if（$ do-> loginCheck（））{echo'loginOk'; } else {'loginError'; } 
  

loginCheck（）是一个无类的simle函数！

你能帮我吗，有什么问题吗？
提前感谢！

解决方案

  $ do = new doClass 
  

您定义了 doClass 参数：

  public function __construct（Database $ db）
  pre> 
 
 
所以你需要提供 Database 类型的参数来成功构造对象。
 
 
 
例如，如果你有一个数据库对象存储在变量 $ database 之前，你可以简单地将它传递给构造函数 doClass 如下：
  $ do = new doClass ; 
  
 
I'm just changing my website's MySQL to PDO, and I've got a strange problem when I tried to use PDO in an other class.
class Database {
private $pdo;

public function __construct() {
    $this->pdo = new PDO('mysql:host=localhost;dbname=appdora;charset=utf8', 'root', 'root');
}
}

class doClass {

//Variables
private $db;

//PDO
public function __construct(Database $db) {
    $this->db = $db;
}
And the code is returns with: the following error:

Catchable fatal error: Argument 1 passed to doClass::__construct() must be an instance of Database, none given, called in .../index.php on line xx and defined in ../classes.php on line xx

The code:
$do = new doClass();
if ($do->loginCheck()) { echo 'loginOk'; } else { 'loginError'; }
loginCheck() is a simle function that works without classes!

Could you help me, what's the problem?
Thanks in advance!
解决方案
$do = new doClass();
You defined your doClass class to expect a parameter in the constructor:
public function __construct(Database $db)
So you need to supply that parameter of type Database to successfully construct the object.

For example, if you have a database object stored before somewhere inside a variable $database, you can simply pass it to the constructor of doClass like this:
$do = new doClass($database);


                        
这篇关于PDO在其他类中有什么问题？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！