silverstripe / silverstripe-asset-admin

        // Configure form to respond to validation errors with form schema

        // if requested via react.

        $form->setValidationResponseCallback(function() use ($form, $file) {

            $schemaId = Controller::join_links($this->Link('schema/FileEditForm'), $file->exists() ? $file->ID : '');

            return $this->getSchemaResponse($form, $schemaId);

        });

        return $form;

    }

        $handler = AddToCampaignHandler::create($this, $record);

        $form = $handler->Form($record);

        $form->setValidationResponseCallback(function() use ($form, $id) {

            $schemaId = Controller::join_links($this->Link('schema/AddToCampaignForm'), $id);

            return $this->getSchemaResponse($form, $schemaId);

        });

        return $form;

    }