对象变量在构造函数中设置后仍然未定义 [英] Object Variable Remains Undefined after being Set in Constructor

问题描述

这是我班级的代码，当然只有相关部分:

This is the code of my class, only relevant parts of course:

class User {
   public $id;

   public function __construct($email, $password, $firstName, $lastName) {
      $db = Connection::getInstance();

      // check if user exists
      $id = User::findUserByEmail($email);
      if($id > 0){
         // echo "User already exists!";
         return -1;
      }

      // Create new row in users table
      $stmt = $db->prepare("INSERT INTO `mapdb`.`user` (`email`, `password`, `firstName`, `lastName`)
                          VALUES (:email, :password, :firstName, :lastName);");
      $stmt->bindParam(':email', $email, PDO::PARAM_STR);
      $stmt->bindParam(':password', $password, PDO::PARAM_STR);
      $stmt->bindParam(':firstName', $firstName, PDO::PARAM_STR);
      $stmt->bindParam(':lastName', $firstName, PDO::PARAM_STR);
      $stmt->execute();

      // check f user added successfully
      $newID = User::findUserByEmail($email);

      if($newID > 0){
         echo "success, ID = ".$newID;
         $this->$id = $newID;
         // $this->$email = $email;
         // $this->$firstName = $firstName;
         // $this->$firstName = $firstName;
      } else {
         echo "failure";
         return -1;
      }
   }
}

我实际调用构造函数的地方:

And where I actually call the constructor:

$user = new User($email, $password, $firstName, $lastName);
echo "<br>userid: ".$user->id; // (<-- this doesn't echo correctly)

无论我怎么尝试，我都无法从 User 对象中获取值.目前我收到以下错误:注意:未定义变量:id

I cannot get the value from the User object whatever I try. At the moment I get the following error: Notice: Undefined variable: id

什么可能拒绝我访问变量?

What could possibly deny me access from the variable?

推荐答案

问题解决了，而不是

$this->$id = $newID;

我应该有

$this->id = $newID;

谢天谢地有 stackoverflow :D

Thank goodness for stackoverflow :D

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