PDO连接MySQL出错解决方案

PDO连接MySQL出错
 
 $dbms = 'mysql';
 $dbName = 'db_mrbook';
 $user = 'root';
 $pwd = '111';
 $host = 'localhost';
 $dsn = "$dbms:host = $host;dbname = $dbName";
 try{
 $pdo = new PDO($dsn,$user,$pwd);
 echo "PDO链接数据库成功";
 }catch(Exception $e){
 echo $e->getMessage()."
";
 }
?>
运行时显示could not find driver
修改了php.ini.dist和php.ini.recommended中的扩展，去掉了extension=php_mysql.dll、extension=php_pdo.dll和extension=php_pdo_mysql.dll前面的分号，重启了Apache，还是同样的错误，请大大帮帮忙阿

------解决方案--------------------
phpinfo() 看看是否加载成功
------解决方案--------------------
看看phpinfo()中的load configure file ，看看加载的是那个php.ini文件
------解决方案--------------------
这样就可以了

PHP code

PDO
PDO support enabled 
PDO drivers  mysql, odbc, sqlite  

pdo_mysql
PDO Driver for MySQL enabled 
Client API version  mysqlnd 5.0.8-dev - 20102224 - $Revision: 308673 $  

PDO_ODBC
PDO Driver for ODBC (Win32) enabled 
ODBC Connection Pooling  Enabled, strict matching  

pdo_sqlite
PDO Driver for SQLite 3.x enabled 
SQLite Library  3.7.4

------解决方案--------------------
你改的php.ini 是否是 Loaded Configuration File 对应的php.ini