带参数的PHP构造函数 [英] PHP constructor with a parameter

问题描述

我需要一个可以执行以下操作的函数:

I need a function that will do something like this:

$arr = array(); // This is the array where I'm storing data

$f = new MyRecord(); // I have __constructor in class Field() that sets some default values
$f->{'fid'} = 1;
$f->{'fvalue-string'} = $_POST['data'];
$arr[] = $f;

$f = new Field();
$f->{'fid'} = 2;
$f->{'fvalue-int'} = $_POST['data2'];
$arr[] = $f;

当我写这样的东西时:

$f = new Field(1, 'fvalue-string', $_POST['data-string'], $arr);
$f = new Field(2, 'fvalue-int', $_POST['data-integer'], $arr);

// Description of parameters that I want to use:
// 1 - always integer, unique (fid property of MyRecord class)
// 'fvalue-int' - name of field/property in MyRecord class where the next parameter will go
// 3. Data for field specified in the previous parameter
// 4. Array where the class should go

我不知道如何用PHP创建参数化的构造函数.

I don’t know how to make a parametrized constructor in PHP.

现在我使用这样的构造函数:

Now I use a constructor like this:

class MyRecord
{
    function __construct() {
        $default = new stdClass();
        $default->{'fvalue-string'} = '';
        $default->{'fvalue-int'} = 0;
        $default->{'fvalue-float'} = 0;
        $default->{'fvalue-image'} = ' ';
        $default->{'fvalue-datetime'} = 0;
        $default->{'fvalue-boolean'} = false;

        $this = $default;
    }
}

推荐答案

阅读所有 构造函数和析构函数 .

Read all of Constructors and Destructors.

构造函数可以像使用PHP中的任何其他函数或方法一样采用参数:

Constructors can take parameters like any other function or method in PHP:

class MyClass {

  public $param;

  public function __construct($param) {
    $this->param = $param;
  }
}

$myClass = new MyClass('foobar');
echo $myClass->param; // foobar

您的构造函数用法示例现在甚至无法编译，因为您无法重新分配$this.

Your example of how you use constructors now won't even compile as you can't reassign $this.

此外，每次访问或设置属性时都不需要大括号. $object->property正常工作.您只需要在特殊情况下使用花括号，例如，如果您需要评估方法$object->{$foo->bar()} = 'test';

Also, you don't need the curly brackets every time you access or set a property. $object->property works just fine. You only need to use curly-brackets under special circumstances like if you need to evaluate a method $object->{$foo->bar()} = 'test';

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