$_GET 变量 - 为什么以前的数据没有隐藏？

Question

我正在创建一个包含类别、子类别和列表的网站。单击一个类别后，即计算页面更改以显示数据库中计算类别中的所有子类别。然后，当单击一个子类别时，将显示该子类别的列表，并将子类别选择发布到 URL。然后，当单击列表时，会发生同样的事情。没关系，但是当我尝试显示列表详细信息时，它应该隐藏列表，但这并没有发生。有谁知道为什么？我使用的代码如下：

<?php
include 'core/init.php';
include 'includes/overall/header.php';
?>

<h1> Computing </h1>

<?php
$subcategory = 'Computing';

if (isset($_GET['subcategory']) && trim($_GET['subcategory']) != '') {
    $subcategory = trim($_GET['subcategory']) != '';
}

$sql = "SELECT * FROM categories WHERE category = '$subcategory' ORDER BY subcategory ASC";
$result = mysql_query($sql) or die(mysql_error() . "<br>" . $sql);
$catNo = 1;
echo "<table class='categorytable'> <tr class='categoryrow'>";
while ($row = mysql_fetch_array($result)) {
    echo '<td class="categorydata"><a href="computing.php?subcategory=' . strtolower($row['subcategory']) . '"><img class="catimg" src="' . $row['subcategory_img_path'] . '" border="0" /></br>' . $row['subcategory'] . '</a></td>';
    if ($catNo % 3 == 0) {

        echo "</tr><tr>";
    }
    $catNo++;
}
echo "</tr> </table>";
?>
<?php
if (isset($_GET['subcategory'])) {
    $subcat = $_GET['subcategory'];

    $sql2 = "SELECT * FROM listings WHERE subcategory = '$subcat' ORDER BY title ASC";
    $result2 = mysql_query($sql2) or die(mysql_error() . "<br>" . $sql2);
    $catNo = 1;
    echo "<table class='categorytable'> <tr class='categoryrow'>";
    while ($row2 = mysql_fetch_array($result2)) {
        echo '<td class="categorydata"><a href="computing.php?subcategory=' . $subcat . '&' . 'listingid=' . ($row2['listing_id']) . '"><img class="catimg" src="' . $row2['main_image'] . '" border="0" /></br>' . $row2['title'] . '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;' . '<i class="fa fa-cog"></i>' . ' ' . $row2['cogs'] . ' per week' . '</a></td>';
        if ($catNo % 3 == 0) {

            echo "</tr><tr>";
        }
        $catNo++;
    }
    var_dump($_GET);


    echo "</tr> </table>";
?>
<?php
    if (isset($_GET['listingid'])) {
        $listingid = $_GET['listingid'];

        $sql3 = "SELECT * FROM listings WHERE listing_id='$listingid'";
        $result3 = mysql_query($sql3) or die(mysql_error() . "<br>" . $sql3);
        while ($row3 = mysql_fetch_assoc($result3)) {
            //whatever your values are
            echo $row3['description'] . "<br />";
        }
    }
}
?>

</br>

<?php
include 'includes/overall/footer.php';
?>

我知道 php_ 函数已被弃用，并且尚未考虑安全性，但当我一切正常时，我会担心这一点。

Answer 1

将 while 部分放入 if。

if(!isset($_GET['subcategory'])){
$sql = "SELECT * FROM categories WHERE category = '$subcategory' ORDER BY subcategory ASC";
$result = mysql_query($sql) or die(mysql_error() . "<br>" . $sql);
$catNo = 1;
echo "<table class='categorytable'> <tr class='categoryrow'>";
while ($row = mysql_fetch_array($result)) {
    echo '<td class="categorydata"><a href="computing.php?subcategory=' . strtolower($row['subcategory']) . '"><img class="catimg" src="' . $row['subcategory_img_path'] . '" border="0" /></br>' . $row['subcategory'] . '</a></td>';
    if ($catNo % 3 == 0) {

        echo "</tr><tr>";
    }
    $catNo++;
}
echo "</tr> </table>";

}

Answer 2

我同意 zairwolf，基本上 Steven 你需要一种方法来标记何时应该显示列表，对页面加载的结构进行一些规划可能会有所帮助。以下是您可能实施的流程，如果我了解您的需求，它可能会改进您的实施。

//Proposed layout

function show_categories () {
   //draw the categories down the left side of screen with "/?category={$record->CATEGORYID}" in anchor href
}

function show_subcategories ($category) {
  //select the subcategories based on the passed category and output also with href as you have already
}

function show_listings ($subcategory) {
  //select all the listings based on the sub category sent here
}

//always show the categories ?
show_categories ();

//other logic when to display sub categories or listings
if ($_REQUEST["subcategory"]) { 
 show_listings ($_REQUEST["subcategory"]);
} else {
 show_subcategories ($_REQUEST["category"])
}

Answer 3

尝试使用 $_POST 方法，它会起作用

Answer 4

我想我找到了更好的解决方案。检查此代码：

<?php
if (isset($_GET['subcategory'])) {
    $subcat = $_GET['subcategory'];

    $sql2 = "SELECT * FROM listings WHERE subcategory = '$subcat' ORDER BY title ASC";
    $result2 = mysql_query($sql2) or die(mysql_error() . "<br>" . $sql2);
    $catNo = 1;
    echo "<table class='categorytable'> <tr class='categoryrow'>";
    while ($row2 = mysql_fetch_array($result2)) {
        echo '<td class="categorydata"><a href="computing.php?listingid=' . ($row2['listing_id']) . '"><img class="catimg" src="' . $row2['main_image'] . '" border="0" /></br>' . $row2['title'] . '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;' . '<i class="fa fa-cog"></i>' . ' ' . $row2['cogs'] . ' per week' . '</a></td>';
        if ($catNo % 3 == 0) {

            echo "</tr><tr>";
        }
        $catNo++;
    }
    var_dump($_GET);


    echo "</tr> </table>";
}
?>
<?php
if (isset($_GET['listingid'])) {
    $listingid = $_GET['listingid'];

    $sql3 = "SELECT * FROM listings WHERE listing_id='$listingid'";
    $result3 = mysql_query($sql3) or die(mysql_error() . "<br>" . $sql3);
    while ($row3 = mysql_fetch_assoc($result3)) {
        //whatever your values are
        echo $row3['description'] . "<br />";
    }
}
?>

在这里，我更改了代码以匹配一种在我看来最接近修复您的代码的观点。由于未根据子类别名称选择列表数据库 table，我们可以做的是将列表块与子类别块分开，如果块在 if (isset($_GET['listingid'])) 之前结束，则 if(isset($_GET['subcategory']))并在您调用列表时从 URL 中删除子类别 GET 变量，这样您就不会运行子类别 if 块。当您在 URL 中为 URL 提供子类别变量时会调用列表，并且在尝试显示您正在显示和隐藏的列表时单独不将子类别提供给 URL页面的那些阶段。您不需要子类别值来显示列表，只需要列表列表，然后您应该只关心 listingid GET 变量。

Answer 5

我认为你的代码没问题，只需要修正这一行：

if (isset($_GET['subcategory']) && trim($_GET['subcategory']) != '') {
    $subcategory = trim($_GET['subcategory']) != '';
}

为什么要为 $subcategory var 分配一个布尔值，然后对其发起查询。声明：

$subcategory = trim($_GET['subcategory']) != '';

如果 $_GET['subcategory'] 不为空或不为空，将给出 1 (TRUE)。您应该将行更改为：

if (isset($_GET['subcategory']) && trim($_GET['subcategory']) != '') {
    $subcategory = trim($_GET['subcategory']);
}

希望对您有所帮助。

Answer 6

使用下面的代码：

<?php
$category = 'Computing';

if (isset($_GET['category']) && trim($_GET['category']) != '') {
    $category = trim($_GET['category']);
}

$sql = "SELECT * FROM categories WHERE category = '$category' ORDER BY category ASC";
$result = mysql_query($sql) or die(mysql_error() . "<br>" . $sql);
$catNo = 1;
echo "<table class='categorytable'> <tr class='categoryrow'>";
while ($row = mysql_fetch_array($result)) {
    echo '<td class="categorydata"><a href="computing.php?category='. $category.'&subcategory=' . strtolower($row['subcategory']) . '"><img class="catimg" src="' . $row['subcategory_img_path'] . '" border="0" /></br>' . $row['subcategory'] . '</a></td>';
    if ($catNo % 3 == 0) {

        echo "</tr><tr>";
    }
    $catNo++;
}
echo "</tr> </table>";
?>
<?php
if (isset($_GET['subcategory'])) {
    $subcat = $_GET['subcategory'];

    $sql2 = "SELECT * FROM subcategory WHERE subcategory = '$subcat' ORDER BY title ASC";
    $result2 = mysql_query($sql2) or die(mysql_error() . "<br>" . $sql2);
    $catNo = 1;
    echo "<table class='categorytable'> <tr class='categoryrow'>";
    while ($row2 = mysql_fetch_array($result2)) {
        echo '<td class="categorydata"><a href="computing.php?category='. $category.'&subcategory=' . $subcat . '&' . 'listingid=' . ($row2['listing_id']) . '"><img class="catimg" src="' . $row2['main_image'] . '" border="0" /></br>' . $row2['title'] . '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;' . '<i class="fa fa-cog"></i>' . ' ' . $row2['cogs'] . ' per week' . '</a></td>';
        if ($catNo % 3 == 0) {

            echo "</tr><tr>";
        }
        $catNo++;
    }
    var_dump($_GET);


    echo "</tr> </table>";
?>
<?php
    if (isset($_GET['listingid'])) {
        $listingid = $_GET['listingid'];

        $sql3 = "SELECT * FROM listings WHERE listing_id='$listingid'";
        $result3 = mysql_query($sql3) or die(mysql_error() . "<br>" . $sql3);
        while ($row3 = mysql_fetch_assoc($result3)) {
            //whatever your values are
            echo $row3['description'] . "<br />";
        }
    }
}
?>

</br>

<?php
include 'includes/overall/footer.php';
?>

$_GET 变量 - 为什么以前的数据没有隐藏？

$_GET variables - Why is previous data not hiding?

php

variables

get

hide