如何从所述类中的类属性上调用`property_exists（）`？

Question

如果我像这样创建类的实例

$template = new EmailTemplate(array('templateFile' =>'template__test.php'));

为什么以下回显NULL？

class EmailTemplate {
    private $templateFile;

    function __construct($args) {
        foreach($args as $key => $val) {
            if(property_exists($this, $this->{$key})) {
                $this->{$key} = $val;
            }
            echo $this->templateFile;
        }
}

我期待构造函数回应＆＃34; template__test.php＆＃34;。

任何帮助？

Answer 1

你应该像这样调用构造函数：

    class EmailTemplate {

        private $templateFile;        

        function __construct( $args ) {

            // Loop through the arguments
            foreach ( $args as $key => $val ) {

                // Check if the current class has a defined variable 
                // named as the value of $val
                if ( property_exists( $this, $key ) ) {

                    // If it has, set it to the passed value
                    $this->$key = $val;

                   // If you pass multiple array items, you should echo $this->$key;
                }

                // Print the defined variable to screen
                echo $this->templateFile;
            }
        }
    }