可捕获的致命错误：类mysql的对象无法转换为字符串 如何删除php中的可捕获错误。我正在处理php代码get-catchable error。是否有人可以帮助我删除此删除。我在其他文件中使用类调用，当我将其对象设置为My-get error时。我看到这是

可捕获的致命错误：类mysql的对象无法转换为字符串 如何删除php中的可捕获错误。我正在处理php代码get-catchable error。是否有人可以帮助我删除此删除。我在其他文件中使用类调用，当我将其对象设置为My-get error时。我看到这是一个简单的错误，也就是我调用函数mysql_-coonect，但仍然存在问题错误。

<?php 
error_reporting(E_ALL);
/*
@ PHP5 Mysql-klasse 
@ Copyright by Web Communication World (www.wccw.in)
@ Diese Klasse darf frei unter diesem Vermerk eingesetzt,
verändert und weitergegeben werden
@ Weitere Klassen, sind auf www.wccw.in Kostenlos erhältlich
Verwendete Funktionen:
@ mysql_connect
@ mysql_select_db
@ mysql_error
@ mysql_query
@ mysql_fetch_array
@ mysql_fetch_assoc
@ mysql_fetch_object
@ mysql_fetch_row
@ mysql_num_rows
@ mysql_real_escape_string
@ mysql_free_result
@ mysql_insert_id
@ mysql_close
@ htmlspecialchars
@ trigger_error
*/
class mysql
{
private $host     = ''; 
private $user     = '';
private $passwort     = ''; 
private $dbname     = '';
private $last_injection = '';
private $conn_id = null;
public function __construct($host, $user, $passwort, $dbname)
{
$this->host     = $host;
$this->user     = $user;
$this->passwort = $passwort;
$this->dbname     = $dbname;
$this->connect_mysql();
return($this->conn_id);
}
private function connect_mysql()
{
$this->conn_id = mysql_connect($this->host,$this->user,$this->passwort);
if($this->conn_id === false)
{
$message  = "Verbindung zur Datenbank nicht m&ouml;glich.<br />\n";
$message .= "Mysql-fehlermeldung: <br />\n";
$message .= mysql_error();
trigger_error($message);
} 
else 
{
$this->select_db();
}
}
private function select_db()
{
$select = mysql_select_db($this->dbname,$this->conn_id);
if($select === false)
    {
        $message  = "Die angegebene Datenbank \"".$this->dbname."\" 
existiert nicht.<br />\n";
        $message .= "Mysql-fehlermeldung: <br />\n";
        $message .= mysql_error();
        trigger_error($message);
    }
}
public function query($sqlcode)
{
    $this->last_injection = mysql_query($sqlcode);
           if($this->last_injection === false)
        {
            $message  = "Fehler bei dem Ausf&uuml;hren eines Mysql-codes!<br />\n";
            $message .= "Mysql-Code: " . htmlspecialchars($sqlcode, ENT_QUOTES) . 
            "<br />\n";
            $message .= "Mysql-fehlermeldung:<br />\n";
            $message .= mysql_error();
            trigger_error($message);
        }
       return($this->last_injection);
}
public function array_result($sql = NULL, &$row = '')
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $row = mysql_fetch_array($inc);
    return($row);
}
public function row_result($sql = NULL, &$row = '')
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $row = mysql_fetch_row($inc);
    return($row);
}
public function object_result($sql = NULL, &$row = '')
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $row = mysql_fetch_object($inc);
    return($row);
}
public function assoc_result($sql = NULL, &$row = '')
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $row = mysql_fetch_assoc($inc);
    return($row);
}
public function num_result($sql = NULL)
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $num = mysql_num_rows($inc);
     return($num);
}
public function sql_string($string)
{
    return(mysql_real_escape_string($string));
}
public function free_result($sql = NULL)
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
     mysql_free_result($inc);
}
public function result($set = 0, $field = 0, $sql = NULL, &$row = '')
{
    $inc = '';
    if($sql === NULL)
    {
        $inc = $this->last_injection;
        } else {
        $inc = $sql;
    }
    $row = mysql_result($result, $set, $field);
    return($row);
}
public function insert_id(&$row = '')
{
    $row = mysql_insert_id();
    return($row);
}
public function close_connect()
{
    mysql_close($this->conn_id);
}
}
class db extends mysql
{
private static $_instance;
public static function getInstance()
{
if( self::$_instance == null )
{
self::$_instance = new db('localhost', 'root', '', 'qcore');
}
return self::$_instance;
}
}
?>

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当我将mysql类的对象设置为I gor error时，哪一行是错误？它抱怨字符串，您是否回显了任何内容，您需要显示您使用该类的代码？请使用完整的错误消息更新您的问题，以及出现错误的代码行。