用php編輯/更新行不起作用/變量未定義

Question

我的代碼有問題：

在編輯頁面上， 我想在輸入框中向用戶顯示先前的值 。

但是，我不斷獲得該值的一個錯誤是：

注意：第72行上C：\\ xampp \\ htdocs \\ website_herkansing \\ edit_gebruiker.php中的未定義變量：gebruikers_naam

我認為isset/submit部分出了問題，但我無法弄清楚。

這是我正在使用的代碼

 <?php

session_start();

define('DB_NAME', 'ochtendgloren');
$servername = "localhost";
$username = "root";
$password = "";
$db = "ochtendgloren";
$tbl = "members";

// Create connection
$conn = new mysqli($servername, $username, $password, $db);
//Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

if (isset($_POST['submit']))
{
    $gebruikers_naam = mysqli_real_escape_string($db, $_POST['gebruikers_naam']);

    htmlentities($gebruikers_naam);

    $id = $_GET['id'];

    $query = "UPDATE members 
    SET gebruikers_naam = '$gebruikers_naam'
    WHERE id = '$id' " ;

    $result = $conn->query($query);

    if($result){
        echo ("<SCRIPT LANGUAGE='JavaScript'>
    window.alert('edit succesvol!')
    window.location.href='admin_members.php';
    </SCRIPT>");
    } 
}
?>

<html>
<head>
    <link rel="stylesheet" href="boekingsform.css">
    <link  rel="stylesheet" href="https://fonts.googleapis.com/css?family=Abel">
</head>

<div class="boeken">
    <h1>Wijzig hier de gebruiker</h1>
    <form action="editrij.php?id=<?= $id ?>"  method="post" >
        <div class="row">
            <div class="col-25">
                <label for="gebruikers_naam"> vul hier de nieuwe gebruikers naam in: </label>
            </div></div>
        <br>
    <div class="row">
        <div class="col-75">
            <input type="text" name="voornaam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>
        </div>
    </div>
<br>
    <input type="submit" value="submit" name="submit" />
    </form>
</div>
</html>

Answer 1

您不是在發送變量gebruikers_naam，而是voornaam。 這行代碼

<input type="text" name="voornaam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>

應該

<input type="text" name="gebruikers_naam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>

另外，由於您在表單中使用變量$ id和$ gebruikers_naam，因此應在if子句之前為它們分配一個值。

Answer 2

我認為問題與您的變量用法和輸入框的名稱有關，它必須是gebruikers_naam

在線：

<input type="text" name="voornaam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>

您只能使用$gebruikers_naam打印名稱。 另外，在if子句中使用全局變量之前，必須先分配一個全局變量。 只需分配空值，例如$gebruikers_naam = ""; 在變量聲明之后。

Answer 3

仍不能完全確定代碼的“流程”是否有意義，但以下內容應有所幫助：

        <?php
session_start();

//define('DB_NAME', 'ochtendgloren'); // not used in your code, commented out
$servername = "localhost";
$username = "root";
$password = "";
$db = "ochtendgloren";
$tbl = "members";

// Create connection
$conn = new mysqli($servername, $username, $password, $db);
//Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

if (isset($_POST['submit']))
{
    if(isset($_POST['gebruikers_naam']) && !empty($_POST['gebruikers_naam'])) { // added condition: we need a 'gebruikers_naam'
    $gebruikers_naam = mysqli_real_escape_string($conn, $_POST['gebruikers_naam']);     // changed $db to $conn

    // the return value (encoded string) of htmlentities is not used in your code
    // so commented it out
    //htmlentities($gebruikers_naam); 

    $id = $_GET['id'];

    $query = "UPDATE members 
    SET gebruikers_naam = '$gebruikers_naam'
    WHERE id = '$id' " ;

    $result = $conn->query($query);
    }

    if($result){
        echo ("<SCRIPT LANGUAGE='JavaScript'>
    window.alert('edit succesvol!')
    window.location.href='admin_members.php';
    </SCRIPT>");
    } else {                                                // added else {} statement
    echo "<script> alert('Error: could not update the database'); </script>"; // added: error message
    }       
}
?>

<html>
<head>
    <link rel="stylesheet" href="boekingsform.css">
    <link  rel="stylesheet" href="https://fonts.googleapis.com/css?family=Abel">
</head>

<div class="boeken">
    <h1>Wijzig hier de gebruiker</h1>
    <form action="editrij.php?id=<?php echo $id; ?>"  method="post" > <!-- you need to echo $id and close with ';' - changed: echo $id; -->
        <div class="row">
            <div class="col-25">
                <label for="gebruikers_naam"> vul hier de nieuwe gebruikers naam in: </label>
            </div></div>
        <br>
    <div class="row">
        <div class="col-75">
            <?php $gebruikers_naam = (isset($gebruikers_naam)) ? $gebruikers_naam : 'N/A'; ?> <!-- added a test to see if $gebruikers_naam is available -->
            <input type="text" name="voornaam" required="required" value="<?php echo $gebruikers_naam; ?>"/> <!-- variable is $gebruikers_naam, changed (echo and ';') -->
        </div>
    </div>
<br>
    <input type="submit" value="submit" name="submit" />
    </form>
</div>
</html>

用php編輯/更新行不起作用/變量未定義

問題描述

3 個解決方案

解決方案1
0 2018-06-12 12:09:14

解決方案2
0 2018-06-12 12:12:51

解決方案3
0 2018-06-12 13:09:16

用php編輯/更新行不起作用/變量未定義

問題描述

3 個解決方案

解決方案1 0 2018-06-12 12:09:14

解決方案2 0 2018-06-12 12:12:51

解決方案3 0 2018-06-12 13:09:16

解決方案1
0 2018-06-12 12:09:14

解決方案2
0 2018-06-12 12:12:51

解決方案3
0 2018-06-12 13:09:16