MySQL插入问题

Question

Im new to PHP/MYSQL so im sry if you feel this is a bad question but i cant get this to work. Its for a login form. The issue i have is with the insert into with the insert query part. I apreciate if anyone could help me get this fixed :) TY in advance.

    function InsertIntoDB(&$formvars)
{

    $confirmcode = $this->MakeConfirmationMd5($formvars['email']);

    $formvars['confirmcode'] = $confirmcode;

    $insert_query = 'insert into '.$this->tablename.'(
            name,
            email,
            username,
            password,
            confirmcode
            )
            values
            (
            "' . $this->SanitizeForSQL($formvars['name']) . '",
            "' . $this->SanitizeForSQL($formvars['email']) . '",
            "' . $this->SanitizeForSQL($formvars['username']) . '",
            "' . md5($formvars['password']) . '",
            "' . $confirmcode . '"
            )';      
    if(!mysqli_query( $this->connection, $insert_query ))
    {
        $this->HandleDBError("Error inserting data to the table
query:$insert_query");
        return false;
    }        
    return true;
}