There is something wrong with my code :
On the edit page, I want to show the user the previous value in the input box .
But one error I keep getting about the value is the following :
: Undefined variable: gebruikers_naam in on line :第行上未定义变量:gebruikers_naam
I think there is something wrong with the isset/submit
part but I just can not figure it out..
Here is the code I'm working with
<?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>
You aren't sending the variable gebruikers_naam, but voornaam. This line of code
<input type="text" name="voornaam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>
Should be
<input type="text" name="gebruikers_naam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>
Also, because you are using the variables $id and $gebruikers_naam in the form, you should assign them a value before the if clause.
I think the problem is related with your variable usage and name of input box it must be gebruikers_naam
On line :
<input type="text" name="voornaam" required="required" value="<?= $gebruikers_naam['gebruikers_naam'] ?>"/>
You may use $gebruikers_naam
only to print the name. Also you must assign a global variable before before using it in if clause. Just assign null like $gebruikers_naam = "";
after variables declarations.
Still not completely sure the 'flow' of your code makes a lot of sense, but following should help a bit:
<?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>
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