duanbiyi7319
2016-03-26 04:28
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在PHP中的未定义索引

I get an error of Undefined index, what is the reason?

while ($row = mysqli_fetch_array($result)) {
        echo "<tr>";

        echo "<td>" . $row['CandidateName'] . "</td>";
        echo "<td>" . $row['Position'] . "</td>";
         echo "<td><input type='radio' name='candidateid' value='".$row['candidateID']."' >";
      echo "<td>" . $row['NumberofVotes'] . "</td>";
        $candidateid=$row['CandidateID'];

    }

Here is the error

Array ( [0] => 1 [CandidateID] => 1 [1] => Jejomar Binay [CandidateName] => Jejomar Binay [2] => President [Position] => President [3] => [NumberofVotes] => ) Array ( [0] => 2 [CandidateID] => 2 [1] => Mar Roxas [CandidateName] => Mar Roxas [2] => President [Position] => President [3] => 1 [NumberofVotes] => 1 )

I will show you now the whole code and the its working now, my output here is to add 1 in number of votes when the radio button is working. it has no error but when i selected the first radio button it only updates the second data.

<html>
        <center>
        <font size="2" face = "century gothic">
        <?php
        $con=mysqli_connect("localhost","root","","election2016");
        // Check connection
        if (mysqli_connect_errno())
        {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
        }
        $result = mysqli_query($con,"SELECT * FROM candidate_info");
        echo "<table border='1'>
        <tr>
        <th>Candidate Name</th>
        <th>Position</th>
        <th>Vote</th>
        <th>Number of Votes</th>
        </tr>";
        while ($row = mysqli_fetch_array($result)) {
            echo "<tr>";

            echo "<td>" . $row['CandidateName'] . "</td>";
            echo "<td>" . $row['Position'] . "</td>";
             echo "<td><input type='radio' name='candidateid' value='".$row['CandidateID']."' >";
          echo "<td>" . $row['NumberofVotes'] . "</td>";
            $candidateID=$row['CandidateID'];

        }
        echo "</table>";
        mysqli_close($con);
        ?>

        <br>
        <br>
        <form method = "post" action = "<?php $_PHP_SELF ?>">
     <input type="text" name="candidateid" value="<?php echo $candidateID;?>">
         <input name = "update" type = "submit" id = "update" value = "update">
        </form>
        </center>
        </font>
        </html>
        <?php
                 if(isset($_POST['update'])) {
                    $dbhost = 'localhost';
                    $dbuser = 'root';
                    $dbpass = '';
 $candidateid = $_POST['candidateid'];
                    $conn = mysql_connect($dbhost, $dbuser, $dbpass);

                    if(! $conn ) {
                       die('Could not connect: ' . mysql_error());
                    }

                    $candidateid = $_POST['candidateid'];


                    $sql = "UPDATE candidate_info SET numberofvotes = 1 WHERE candidateid = '$candidateid'" ;
                    mysql_select_db('election2016');
                    $retval = mysql_query( $sql, $conn );

                    if(! $retval ) {
                       die('Could not update data: ' . mysql_error());
                    }
                    echo "Updated data successfully
";

                    mysql_close($conn);
                 }
        ?>
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