PHP中未定义的变量警告

Question

所以我一直在做这个学校项目，需要做它，这样我就可以编辑表中的任何内容。每当我点击"；编辑"；它正确地重定向了我，但在形式上它说有一个未定义的变量event，尽管这个变量几乎在任何地方都被使用。这是表格的一些代码：

<table style='margin-left:auto ; margin-right:auto;'>
<tr>
<th>#</th>
<th>Name</th>
<th>Zeit</th>
<th>Datum</th>
<th>Titel</th>
<th>Inhalt</th>
<th>Ort</th>
</tr>
<?php
if($stmt=$db->prepare("SELECT * FROM terminkalender")) {
$stmt->execute();
$stmt->store_result();
$zeilen = $stmt->num_rows();
$stmt->close();
}else {
$zeilen = 0;
}
if($zeilen > 0) {
//nur wenn Einträge, dann ausgeben
if($stmt = $db->prepare("SELECT * FROM terminkalender ORDER BY zeit,datum DESC")) {
$stmt->execute();
$stmt->bind_result($id,$name,$zeit,$datum,$ort,$titel,$inhalt);
$stmt->store_result();
//Ausgabe starten
while($stmt->fetch()){
echo "<tr>";
?>
<td><?php echo $id ;?></td>
<td><?php echo htmlspecialchars($name) ;?></td>
<td><?php echo htmlspecialchars($datum) ;?></td>
<td><?php echo htmlspecialchars($zeit) ;?></td>
<td><?php echo htmlspecialchars($ort) ;?></td>
<td><?php echo htmlspecialchars($titel) ;?></td>
<td><?php echo htmlspecialchars($inhalt); ?></td>
<td><a href='edit.php?id=<?php echo $id;?>'>Edit</a></td>
<td><a href='delete.php?id=<?php echo $id;?>'>Delete</a></td>
<?php 
echo "</tr>" ;

}
}
}
?>
</table>

这里是edit.php文件：

<?php
include("./config/connect.inc.php");
$id = $_GET['id']; // get id through get string
$result=mysqli_query($db,"SELECT * FROM terminkalender WHERE id=$id");
if(isset($_POST['update'])) {
$name=$_POST['name'];
$datum=$_POST['datum'];
$zeit=$_POST['zeit'];
$ort=$_POST['ort'];
$titel=$_POST['titel'];
$inhalt=$_POST['inhalt'];
$result = "UPDATE terminkalender 
SET name='$name',
datum='$datum',
zeit='$zeit',
ort='$ort',
titel='$titel',
inhalt='$inhalt' 
WHERE id=$id";
header("location: ausgabe.php");
}
?>
<form name="form" method="POST" action="edit.php">
<input type="text" name="name" value="<?php echo $name; ?>" Required>
<input type="date" name="datum" value="<?php echo $datum; ?>" Required>
<input type="time" name="zeit" value="<?php echo $zeit; ?>" Required>
<input type="text" name="ort" value="<?php echo $ort; ?>" Required>
<input type="text" name="titel" value="<?php echo $titel; ?>" Required>
<input type="text" name="inhalt" value="<?php echo $inhalt; ?>" Required>
<input type="hidden" name="id" value="<?php echo $_GET['id']; ?>">
<input type="submit" name="update" value="Update">
</form>

Ẁ如果有人能帮忙，那就太棒了。感谢是提前！

Answer 1

也许您可以尝试使用php的isset函数来检查该变量是否包含值，以查看更多详细信息：-https://www.stechies.com/notice-undefined-variable-in-php/