[英]Getting Trying to get property of non-object in " after deleting a object in database with select input
當我再次更新頁面時,他們會出現......
因為錯誤我得到“注意:嘗試在刪除后獲取非對象的屬性”
我正在使用PHP,一切正常,但我刪除后選擇輸入中沒有選項。
這是我的代碼,在Stackoverflow btw上是即時消息
if(isset($_POST['endreProve']) || (isset($_POST['slettSpm']) )){
if(isset($_POST['slettSpm'])){
$spmId = $_POST['spmId'];
$sql = "DELETE FROM `alternativ` WHERE `SpormalId`= $spmId;";
$sql .= "DELETE FROM `sporsmal` WHERE `sporsmal`.`SporsmalId` = $spmId";
(mysqli_multi_query($conn, $sql));// {
}
if(isset($_POST['endreProve'])){
$id = $_POST['endreProve'];
$id2 = explode('- ', $id);
$_SESSION['proveId'] = $id2[1];
}
$id = $_SESSION['proveId'];
?>
<form style="padding-left: 30px; padding-top: 15px;" action="Rediger.php" method="POST">
<div class='form-group row'> <div class='col-sm-12'>
<h2><b> Prøve <?php echo $id ?> </b></h2>
<label>Velg spørsmål:</label>
<select name="spmId">
<?php
$prove = "SELECT * FROM prove As p
INNER JOIN sporsmal As s ON p.ProveId = s.ProveId
INNER JOIN alternativ As alt ON s.SporsmalId = alt.SpormalId
WHERE p.ProveId = $id";
$sql = "SELECT * FROM sporsmal WHERE ProveId = $id";
$prove_result = $conn->query($sql);
if($prove_result->num_rows > 0) {
while($row = $prove_result->fetch_assoc()){
$sporsmal = $row["Sporsmal"];
$sporsmalId = $row["SporsmalId"];
$svar = $row["Svar"];
echo "<option value='$sporsmalId'>$sporsmal</option>";
}
}
?>
</select>
<input type='submit' class='btn btn-primary btn-sm' name='endreSpm' value='Endre'>
<input type='submit' class='btn btn-danger btn-sm' name='slettSpm' value='Slett'><br/><br/>
<label><b>Legg til spørsmål</b></label><br/>
<div class="form-group">
<input type="text" class="col-sm-6" name="spm" placeholder="Spørsmål?" />
<input type="text" name="riktig" placeholder="svar" id="svar" readonly /><br/>
</div>
<div class="input-group">
Skriv og velg riktig alternativ:
<div class="input-group-prepend">
<input type="text" id="alt1" name="alt1" placeholder="Alternativ1" id="1">
<div class="input-group-text">
<input type="radio" name="alt" value="1" onclick='bytteSvar(this.value)'>
</div>
</div>
<div class="input-group-prepend">
<input type="text" id="alt2" name="alt2" placeholder="Alternativ2" id="2">
<div class="input-group-text">
<input type="radio" name="alt" value="2" id="alt2" onclick='bytteSvar(this.value)' >
</div>
</div>
<div class="input-group-prepend">
<input type="text" id="alt3" name="alt3" placeholder="Alternativ3">
<div class="input-group-text">
<input type="radio" name="alt" value="3" id="alt3" onclick='bytteSvar(this.value)'>
</div>
</div>
<div class="input-group-prepend">
<input type="text" id="alt4" name="alt4" placeholder="Alternativ4" >
<div class="input-group-text">
<input type="radio" name="alt" value="4" id="alt4" onclick='bytteSvar(this.value)'>
</div>
</div>
<br/>
<div class="input-group-prepend">
<input type="text" name="media" placeholder="Media - /path/path" >
 <input type="submit" name="leggTilSpm" value="Legg til" class="btn btn-success btn-sm">
</div>
</div>
</div>
</div>
<?php
}
在為選擇列表創建選項的代碼部分中,您使用的是查詢,該查詢引用名稱為$id
的變量。 刪除行時不會更新此值。 您正在使用會話中的舊值。 即使在刪除時,也需要更新會話中的值。
<?php
if (isset($_POST['endreProve']) || (isset($_POST['slettSpm']) )) {
if (isset($_POST['slettSpm'])){
$spmId = $_POST['spmId'];
$sql = "DELETE FROM `alternativ` WHERE `SpormalId`= $spmId;";
$sql .= "DELETE FROM `sporsmal` WHERE `sporsmal`.`SporsmalId` = $spmId";
(mysqli_multi_query($conn, $sql));
}
// !!! This is left out when you delete
if (isset($_POST['endreProve'])){
$id = $_POST['endreProve'];
$id2 = explode('- ', $id);
$_SESSION['proveId'] = $id2[1];
}
// !!! old session value is used instead, which refers to an deleted entry
$id = $_SESSION['proveId'];
?>
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