PHP类：什么时候使用:: vs. - &gt ;? [英] PHP Classes: when to use :: vs. ->?

问题描述

我知道有两种方法可以访问PHP类 - ::和 - >。有时一个似乎为我工作，而另一个没有，我不明白为什么。

I understand that there are two ways to access a PHP class - "::" and "->". Sometime one seems to work for me, while the other doesn't, and I don't understand why.

每个的好处是什么，什么是权利

What are the benefits of each, and what is the right situation to use either?

推荐答案

简单地说， :: 属性， - > 用于对象级属性。

Simply put, :: is for class-level properties, and -> is for object-level properties.

如果属性属于类，请使用 ::

If the property belongs to the class, use ::

属于 类的实例，请使用 - >

If the property belongs to an instance of the class, use ->

class Tester
{
  public $foo;
  const BLAH;

  public static function bar(){}
}

$t = new Tester;
$t->foo;
Tester::bar();
Tester::BLAH;

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