Codeigniter - Call to Undefined Function mysqli_connect()

Question

I am using CI in version 2.2.5 and I have an error in my project.

Error: Fatal error: Uncaught Error: Call to Undefined Function mysqli_connect() in C:\

local: system database drivers mysqli mysqli_driver.php on line 77

File function, line 77 mysqli_driver.php

function db_connect()
{
    if ($this->port != '') {
        return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database, $this->port);
    } else {
        return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database);
    }
}

I’m using php 7.

Does anyone know how to solve this? Thank you

Detail: I have already enabled mine extension=php_mysqli.dll in the php.ini

In the archive config/database.php I’ve already changed to $db['default']['dbdriver'] = 'mysqli';

but the error continues