Grid/Grid.php
protected function processExports($exportId)
    {
        if ($exportId > -1 && '' !== $exportId) {
            if (array_key_exists($exportId, $this->exports)) {
                $this->isReadyForExport = true;

                $this->processSessionData();
                $this->page = 0;
                $this->limit = 0;
                $this->prepare();

                $export = $this->exports[$exportId];
                if ($export instanceof ContainerAwareInterface) {
                    $export->setContainer($this->container);
                }
                $export->computeData($this);

                $this->exportResponse = $export->getResponse();

                return true;
            } else {
                throw new \OutOfBoundsException(sprintf(self::EXPORT_NOT_DEFINED_EX_MSG, $exportId));
            }
        }

        return false;
    }
protected function processExports($exportId)
    {
        if ($exportId > -1 && '' !== $exportId) {
            if (array_key_exists($exportId, $this->exports)) {
                $this->isReadyForExport = true;

                $this->processSessionData();
                $this->page = 0;
                $this->limit = 0;
                $this->prepare();

                $export = $this->exports[$exportId];
                if ($export instanceof ContainerAwareInterface) {
                    $export->setContainer($this->container);
                }
                $export->computeData($this);

                $this->exportResponse = $export->getResponse();

                return true;
            } else {
                throw new \OutOfBoundsException(sprintf(self::EXPORT_NOT_DEFINED_EX_MSG, $exportId));
            }
        }

        return false;
    }
Process exports.

@param int $exportId

@throws \OutOfBoundsException

@return bool