在 PHP 中为对象添加属性
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Add attribute to an object in PHP
提问by igorgue
How do you add an attribute to an Object in PHP?
你如何在 PHP 中为对象添加属性？
回答by Pekka
Well, the general way to add arbitrary properties to an object is:
好吧，向对象添加任意属性的一般方法是：
$object->attributename = value;
You can, much cleaner, pre-define attributes in your class (PHP 5+ specific, in PHP 4 you would use the old var $attributename)
您可以更清晰地在类中预定义属性（特定于 PHP 5+，在 PHP 4 中您将使用旧的var $attributename）
class baseclass
{
public $attributename; // can be set from outside
private $attributename; // can be set only from within this specific class
protected $attributename; // can be set only from within this class and
// inherited classes
this is highly recommended, because you can also document the properties in your class definition.
这是强烈推荐的，因为您还可以在类定义中记录属性。
You can also define getter and setter methodsthat get called whenever you try to modify an object's property.
您还可以定义getter 和 setter 方法，每当您尝试修改对象的属性时，它们都会被调用。
回答by jordanstephens
Take a look at the php.net documentation: http://www.php.net/manual/en/language.oop5.properties.php
看看 php.net 文档：http://www.php.net/manual/en/language.oop5.properties.php
Attributes are referred to as "properties" or "class members" in this case.
在这种情况下，属性被称为“属性”或“类成员”。
回答by David Morrow
this is a static class but, the same principle would go for an intantiated one as well. this lets you store and retrieve whatever you want from this class. and throws an error if you try to get something that is not set.
这是一个静态类，但同样的原则也适用于一个拟定的类。这使您可以从此类中存储和检索您想要的任何内容。如果您尝试获取未设置的内容，则会引发错误。
class Settings{
protected static $_values = array();
public static function write( $varName, $val ){
self::$_values[ $varName ] = $val;
}
public static function read( $varName ){
if( !isset( self::$_values[ $varName ] )){
throw new Exception( $varName . ' does not exist in Settings' );
}
return self::$_values[ $varName ];
}
}
