访问 URL 时为 foreach() 提供的参数无效

Question

我现在有两个页面，分别称为 index.php 和 checkout.php。

在 index.php 页面中，我有 2 个复选框和 4 个单选按钮。

我正在做的是，当用户选中复选框和单选按钮并单击提交按钮时，我将复选框和单选按钮的值发送到 checkout.php 页面 并且该值将调用我的查询以在我的结帐页面上显示输出。

我尝试使用SESSION 将数据从一页发送到另一页，它正在工作。我在结帐页面上获得了POST 数据，并且我也在获得查询的输出。

现在我的问题是，如果我刷新页面，那么没有问题，但是当我点击 URL 时，我得到了错误

警告：为 foreach() 提供的参数无效 /home4/test/example/checkout.php 第 70 行

index.php

<form action="checkout.php" method="post" name="form1">
    <div class="formWrapper">
        <div class="form-group">
            <fieldset>
            <input type="checkbox"  name="fruit[1]"  value="1"><label>Fruit One</label><br />
            <input type="radio"  name="color[1]"  value="1"><label>Black</label>
            <input type="radio"  name="color[1]"  value="2"><label>Yellow</label>
            </fieldset>
        </div>
        <div class="form-group">
            <fieldset>
            <input type="checkbox"  name="fruit[2]"  value="2"><label>Fruit Two</label><br />
            <input type="radio"  name="color[2]"  value="1"><label>Black</label>
            <input type="radio"  name="color[2]"  value="2"><label>Yellow</label>
            </fieldset>
        </div>
        <input type="submit" name="submit" value="Next">
    </div>
</form>

checkout.php

<?php
session_start();
 include('connection.php');
 if(isset($_POST['submit'])){
 $_SESSION['fruits']=$_POST['fruit'];
 $_SESSION['colors']=$_POST['color'];
  
  foreach ($_SESSION['fruits'] as $key => $value) {
  try{
     $sqlquery="SELECT col1,col2, (select demoCol from tbl_colors where c_id=:c_id) as demoColor FROM tbl_mytable WHERE id=:id and is_active=1";
    $stmt = $pdo->prepare($sqlquery);
     $stmt->execute( array(':c_id' => $_SESSION['colors'][$key],':id'=>$_SESSION['fruits'][$key]) );
    $result = $stmt->fetchAll();
     foreach ($result as $row) {?>
        <h3><?php echo $row['col1'];?> <?php echo $row['col2'];?></h3>
        <p><?php echo $row['demoColor'];?></p>
<?php
     }
 }
 catch(PDOException $e) {
  echo "Error: " . $e->getMessage();
  }
}
 }
 ?>

Answer 1

快速浏览您的代码，我认为您可以稍微修改一下

<?php

    session_start();
    /*
        `fruit` and `color` MUST be available
        before attempting to assign as any 
        sort of variable - so test here!
    */
    if( isset( 
            $_POST['submit'],
            $_POST['fruit'],
            $_POST['color']
        )){
        
        
        include('connection.php');
        /*
            It is not entirely clear why you would want to assign
            session values directly from POST values when you could
            simply work with the POST values instead.
        */
        $fruits=$_POST['fruit'];
        $colours=$_POST['color'];
        
        /*
            create the sql statement with placeholders
            which are then bound as parameters when the
            statement is executed.
            
            Create the statement once and assign new values
            inside of any loops rather than re-stating it
            on each iteration.
        */
        $sql='select `col1`, `col2`, ( select `democol` from `tbl_colors` where `c_id`=:cid ) as `democolor`
                from `tbl_mytable`
                where `id`=:id and `is_active`=1';
        
        $stmt=$pdo->prepare( $sql );

        
        
        /*
            Process the POSTed variables
            using the $key to access the values
            within the other array ( colours )
        */
        foreach( $fruits as $key => $value ) {
            try{
                if( isset( $colours[ $key ] ) ){
                    $stmt->execute( array(
                        ':cid'  =>  $value,
                        ':id'   =>  $colours[ $key ]
                    ));
                    $result = $stmt->fetchAll();
                    foreach( $result as $row ) {
?>
                    <h3>
                        <?php echo $row['col1'];?>
                        <?php echo $row['col2'];?>
                    </h3>
                    <p><?php echo $row['demoColor'];?></p>
<?php
                    }
                }
            } catch( PDOException $e ) {
                echo "Error: " . $e->getMessage();
            }
        }
    }
?>

仔细检查表明，您可能只有一个 SQL 查询来检索所有记录，方法是最初处理 POST 数据并生成包含各种 ID 的合适字符串，以便您在 sql 中使用 IN 运算符 - 例如如 where id IN (1,2,3) 等 - 比如：

$sql='select `col1`, `col2`, ( select `democol` from `tbl_colors` where `c_id` IN ( :cids ) ) as `democolor`
        from `tbl_mytable`
        where `id` IN ( :ids ) and `is_active`=1';
$stmt=$pdo->prepare( $sql );

$args=array(
    ':cids' =>  implode(',',array_values( $colours ) ),
    ':ids'  =>  implode(',',array_values( $fruits ) )
);

$stmt->execute( $args );

我希望这可能有用 - 我应该强调没有经过测试，所以可能会有错误，但希望不会。