public function validateMinLength()
    {
        $val = $this->val();

        if ($val === null) {
            return $this->allowNull();
        }

        $minLength = $this->minLength();
        if ($minLength == 0) {
            return true;
        }

        if ($val === '' && $this->allowEmpty()) {
            // Don't check empty string if they are allowed
            return true;
        }

        if (is_string($val)) {
            $valid = (mb_strlen($val) >= $minLength);
            if (!$valid) {
                $this->validator()->error('Minimum length error', 'minLength');
            }
        } else {
            $valid = true;
            foreach ($val as $v) {
                $valid = (mb_strlen($v) >= $minLength);
                if (!$valid) {
                    $this->validator()->error('Minimum length error', 'minLength');
                    return $valid;
                }
            }
        }

        return $valid;
    }