mysql_real_escape_string转换为mysqli

Question

我试图将mysql_real_escape_string（）转换为mysqli并一直在尝试：

$mysqli->real_escape_string($this->email);

然而，这会出现错误并且似乎不起作用。错误：

Undefined variable: mysqli in..

...其中涉及此行：$mysqli->real_escape_string($this->name),

有关如何在我的设置中使用此功能的任何建议？

class registerForm {

    var $name;
    var $email;

    function registerContactFormular(){

    }

    function init() {
        //some different init stuff

        return true;
    }

    function save() {
        if(isset($_REQUEST['field'])) {
            $sql = sprintf("
            INSERT INTO contact (
            name,
            email)
            VALUES ('%s','%s','%s)",
            mysqli_real_escape_string($this->name),
            mysqli_real_escape_string($this->email));

            $res = mysql_query($sql) or die( mysql_error());
        }

        if($res) {
            return true;
        }
    }

}