Select the Use Document ID as output filename
check box to rename each downloaded file using the value of its ObjectID attribute.
Since a file in GridFS is distinct by ID rather than by name, it is possible
that several files are using the same file name. For this reason, when
downloading this kind of files into the same directory without renaming them
differently, an exception is returned to alert that the file being downloaded
already exists. In order to avoid this error, you can either select the
Overwrite local files check box to replace the
existing one with the latest downloaded file or rename these files on the fly
using their IDs. In this example, the strategy of renaming these files is
adopted.
