Question

我想对PHP嵌套if / else提供一些帮助。似乎我的代码中的最后else应检查用户是否已登录，这给了我期待的语句错误。整个代码很好但是最后else。

这是页面上的错误：

解析错误：语法错误，意外＆＃39;否则＆＃39;第141行的create_topic.php中的（T_ELSE）

虽然我理解这是因为现在的最后一个被视为额外的else，我似乎无法弄清楚为什么因为我使用我的IDE来仔细检查我的陈述似乎都是平衡的。

<?php include "_class/core.php"; ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>Promanage</title>
<link rel="stylesheet" href="_css/style.css" type="text/css" />
</head>
<body>
<div id="main">

    <?php
    if(!empty($_SESSION['LoggedIn']) && !empty($_SESSION['Username']))
    {

        $username = $_SESSION['Username'];

       ?>


        <h1>Profile</h1>
        <a href="index.php" rel="nofollow">Home</a> <a href="profile.php" rel="nofollow">Profile</a> <a href="logout.php" rel="nofollow">Logout</a> <br /><br />

<?php

        if($_SERVER['REQUEST_METHOD'] != 'POST')
        { 
            $sql = "SELECT
        course_id,
        course_name,
        course_description
        FROM
        course";

            $result = mysql_query($sql);

            if(!$result)
            {
                //the query failed, uh-oh :-(
                echo 'Error while selecting from database. Please try again later.';
            }
            else
            {
                if(mysql_num_rows($result) == 0)
                {
                    if($_SESSION['user_level'] == 1)
                    {
                        echo 'You have not created courses yet.';
                    }
                    else
                    {
                        echo 'Before you can post a topic, you must wait for an admin to create some categories.';
                    }
                }
                else
                {

                    echo '<form method="post" action="">
        Subject: <input type="text" name="topic_subject" />
        Category:';

                    echo '<select name="topic_cat">';
                    while($row = mysql_fetch_assoc($result))
                    {
                        echo '<option value="' . $row['course_id'] . '">' . $row['course_name'] . '</option>';
                    }
                    echo '</select>';

                    echo 'Message: <textarea name="post_content" /></textarea>
        <input type="submit" value="Create topic" />
    </form>';
                }
            }
        }
        else
        {
            $query  = "BEGIN WORK;";
            $result = mysql_query($query);

            if(!$result)
            {
                echo 'An error occured while creating your topic. Please try again later.';
            }
            else
            {
                $sql = "INSERT INTO
           topics(topic_subject,
           topic_date,
           topic_cat,
           topic_by)
           VALUES('" . mysql_real_escape_string($_POST['topic_subject']) . "',
           NOW(),
           " . mysql_real_escape_string($_POST['topic_cat']) . ",
           " . $_SESSION['user_id'] . "
           )";

                $result = mysql_query($sql);
                if(!$result)
                {
                    echo 'An error occured while inserting your data. Please try again later.' . mysql_error();
                    $sql = "ROLLBACK;";
                    $result = mysql_query($sql);
                }
                else
                {
                    $topicid = mysql_insert_id();

                    $sql = "INSERT INTO
           posts(post_content,
           post_date,
           post_topic,
           post_by)
           VALUES
           ('" . mysql_real_escape_string($_POST['post_content']) . "',
           NOW(),
           " . $topicid . ",
           " . $_SESSION['user_id'] . "
           )";
                    $result = mysql_query($sql);

                    if(!$result)
                    {
                        echo 'An error occured while inserting your post. Please try again later.' . mysql_error();
                        $sql = "ROLLBACK;";
                        $result = mysql_query($sql);
                    }
                    else
                    {
                        $sql = "COMMIT;";
                        $result = mysql_query($sql);

                        echo 'You have successfully created <a href="topic.php?id='. $topicid . '">your new topic</a>.';
                    }
                }
            }
        }
    }
    ?>

    <?php
    else
    {
    ?>


        <h1>Member Login</h1>

        <p>Thanks for visiting! Please either login below, or <a href="register.php">click here to register</a>.</p>

        <form method="post" action="index.php" name="loginform" id="loginform">
            <fieldset>
                <label for="username">Username:</label><input type="text" name="username" id="username" /><br />
                <label for="password">Password:</label><input type="password" name="password" id="password" /><br />
                <input type="submit" name="login" id="login" value="Login" />
            </fieldset>
        </form>

    <?php 
    }
    ?>


</div>
</body>
</html>

这是发出错误的确切部分。

<?php
    else
    {
    ?>


        <h1>Member Login</h1>

        <p>Thanks for visiting! Please either login below, or <a href="register.php">click here to register</a>.</p>

        <form method="post" action="index.php" name="loginform" id="loginform">
            <fieldset>
                <label for="username">Username:</label><input type="text" name="username" id="username" /><br />
                <label for="password">Password:</label><input type="password" name="password" id="password" /><br />
                <input type="submit" name="login" id="login" value="Login" />
            </fieldset>
        </form>

    <?php
    }
    ?>

Answer 1

您的代码可以简化为：

<div>
  <?php
    if(true)
    {
    }
  ?>
  <?php
    else
    {
    }
  ?>
</div>

问题是PHP认为你只有一个没有if语句的else。然后，当它到达else时，它无法做任何事情。这就是你得到错误的原因：

Parse error: syntax error, unexpected T_ELSE in

解决方案是将右括号移动到包含else语句的块：

<div>
  <?php
    if(true)
    {
  ?>
  <?php
    }
    else
    {
    }
  ?>
</div>

嵌套if else语句，期望语句错误

1 个答案: