按字符串实例化类

Question

我有这段代码。

    $contrl = stripslashes($this->params['controller'].'Controller'); //PostController
    $obj = new $contrl(); // What's won't work
    //this don't work too
    $contrl = 'PostController';
    $obj = new $contrl();
    //but this work good
    $obj = new PostController();

我不明白为什么会发生这种情况以及如何解决它？

Answer 1

我还没有对它进行过测试，但我很确定应该这样做（as per the doc）：

$obj = new $contrl;