Question

我正在尝试调用一个名为displaySentence（）的函数，并将其输入“candy”的值输入到candycontest.php的表单中。该函数最终将具有更多功能，但是现在我只是想要回显该句子的值以确保函数正常工作。当我运行脚本时，页面会显示，直到它进入我的功能，此时它是空白的。

candycontest.php

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Pete's Treats Candy Contest</title>
</head>
<body>
    <form action="checkticket.php" method="post">
        <label for="ticketNum">Enter your ticket number:</label>
        <input type="number" name="ticketNum" style="width:100px"><br/>
        <label for="sentence">Enter the magic sentence:</label>
        <input type="text" name="sentence" style="width:600px"><br/>
        <input type="submit" value="Am I a Winner?">
    </form>
</body>
</html>

checkticket.php

<?php

$userTicket = $_POST['ticketNum'];


class MagicSentence {
public $sentence;


public function __construct($sentence) {
    $this->setSentence($sentence);
}

public function getSentence() { return $this->sentence; }
public function setSentence($sentence) {
    $this->sentence = $sentence;
}
} // End class MagicSentence



class Ticket extends MagicSentence {
public $ticketNum;

public function displaySentence() {
    $userSentence = $_POST['sentence'];
    echo $userSentence;
}
}

$magicSentence = new MagicSentence("The cow jumped over the moon.");
?>



<html>
<head>
    <meta charset="utf-8">
    <title>Pete's Treats Candy Contest</title>
</head>
<body>
    <?php 


        echo 'Your ticket number is: ' . $userTicket . "<br>";
        echo 'The magic sentence is: ' . $magicSentence->getSentence() .     "<br>";

        displaySentence();

    ?>
</body>
</html>

Answer 1

将$magicSentence = new MagicSentence("The cow jumped over the moon.");更改为$magicSentence = new Ticket("The cow jumped over the moon.");

您需要这样做，因为displaySentence()类（延伸到Ticket类）下存在MagicSentence方法。

另外，将displaySentence();更改为$magicSentence->displaySentence();以便调用您的方法。你不能像普通函数一样调用方法。

那样做，你应该是金色的。

Answer 2

创建类Ticket，$ticketObj的对象，并使用$ticketObj->displaySentence();代替displaySentence();

Answer 3

displaySentence();是Ticket类的一种方法，您从未实例化过某个对象，因此它在任何上下文中都不存在。

$magicSentence = new MagicSentence("The cow jumped over the moon."); 需要是： $magicSentence = new Ticket("The cow jumped over the moon.");

和 displaySentence();需要：$magicSentence->displaySentence();

在PHP中调用函数

3 个答案: