您可以在PHP中动态创建实例属性吗？ [英] Can you create instance properties dynamically in PHP?

问题描述

有没有办法动态创建所有实例属性？例如，我希望能够在构造函数中生成所有属性，并且在类被实例化之后仍然可以访问它们： $ object-> property 。请注意，我想单独访问属性，而不是使用数组;以下是我不想要的的示例：

  class Thing {
 public $性能; 
函数__construct（array $ props = array（））{
 $ this-> properties = $ props; 
} 
} 
 $ foo = new Thing（array（'bar'=>'baz'）; 
＃我不想这样做：
 $ foo-> properties ['bar']; 
＃我想这样做：
 // $ foo-> bar; 
 更具体来说，当我处理具有大量属性的类时，我希望能够选择所有列中的所有列。数据库（表示属性）并从中创建实例属性，每个列值应存储在单独的实例属性中。
解决方案
 Sort of。有一些魔法方法，可以让你自己编写代码，以便在运行时实现类的行为：
  class foo {
 public function __get（$ name）{
 return（'dynamic！'）; 
} 
 public function __set（$ name，$ value）{
 $ this-> internalData [$ name] = $ value; 
} 
} 
  
这是动态吸气剂的一个例子d setter方法，它允许您在访问对象属性时执行行为。例如
  print（new foo（） - > someProperty）; 
  
将打印，在这种情况下，动态！并且您还可以为任意命名的属性分配一个值，在这种情况下，__set（）方法被默认调用。 __call（$ name，$ params）方法对于对象方法调用也是一样的。在特殊情况下非常有用但是大多数情况下，你会得到：
  class foo {
 public function __construct（）{ 
 foreach（getSomeDataArray（）as $ k => $ value）
 $ this-> {$ k} = $ value; 
} 
} 
  
 ...因为大多数情况下，你需要的是将数组的内容转储到相应命名的类字段中，或至少在执行路径中非常明确的点处。因此，除非您真的需要动态行为，否则请使用最后一个示例来填充数据。
 
 
这称为重载
  http://php.net/manual/en/language.oop5.overloading.php  
 
 
 
Is there any way to create all instance properties dynamically? For example, I would like to be able to generate all attributes in the constructor and still be able to access them after the class is instantiated like this: $object->property. Note that I want to access the properties separately, and not using an array; here's an example of what I don't want:
class Thing {
    public $properties;
    function __construct(array $props=array()) {
        $this->properties = $props;
    }
}
$foo = new Thing(array('bar' => 'baz');
# I don't want to have to do this:
$foo->properties['bar'];
# I want to do this:
//$foo->bar;
To be more specific, when I'm dealing with classes that have a large number of properties, I would like to be able to select all columns in a database (which represent the properties) and create instance properties from them. Each column value should be stored in a separate instance property.
解决方案
Sort of. There are magic methods that allow you to hook your own code up to implement class behavior at runtime:
class foo {
  public function __get($name) {
    return('dynamic!');
  }
  public function __set($name, $value) {
    $this->internalData[$name] = $value;
  }
}
That's an example for dynamic getter and setter methods, it allows you to execute behavior whenever an object property is accessed. For example
print(new foo()->someProperty);
would print, in this case, "dynamic!" and you could also assign a value to an arbitrarily named property in which case the __set() method is silently invoked. The __call($name, $params) method does the same for object method calls. Very useful in special cases. But most of the time, you'll get by with:
class foo {
  public function __construct() {
    foreach(getSomeDataArray() as $k => $value)
      $this->{$k} = $value;
  }
}
...because mostly, all you need is to dump the content of an array into correspondingly named class fields once, or at least at very explicit points in the execution path. So, unless you really need dynamic behavior, use that last example to fill your objects with data.

  
This is called overloading
  http://php.net/manual/en/language.oop5.overloading.php


                        
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