[英]How to get Parent class variable value in child class construct method
我有兩個文件:
ParentClass.php
<?php
class ParentClass {
public $variable1;
public $variable2 = "Value of variable 2";
public function __construct()
{
$this->variable1 = "Value of variable 1";
}
}
$obj = new ParentClass;
?>
和 ChildClass.php
<?php
include "ParentClass.php";
class ChildClass extends ParentClass {
public function __construct()
{
echo $this->variable1;
echo $this->variable2;
}
}
$obj = new ChildClass;
?>
當我在瀏覽器中運行 ChildClass 文件時,它只給了我變量 2 的值。它沒有顯示變量 1 的值。 我需要打印 variable1 和 variable2 值。 請幫忙。
你需要在你的子結構中調用 parent::__construct()
工作代碼應該是:
ParentClass.php
<?php
class ParentClass {
public $variable1;
public $variable2 = "Value of variable 2";
public function __construct()
{
$this->variable1 = "Value of variable 1";
}
}
$obj = new ParentClass;
?>
和 ChildClass.php
<?php
include "ParentClass.php";
class ChildClass extends ParentClass {
public function __construct()
{
parent::__construct(); // like this
echo $this->variable1;
echo $this->variable2;
}
}
$obj = new ChildClass;
?>
試試這個,看看它是否有效:)
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