AddDirectoryByName Method (directoryNameInArchive)

Use this when you want to create a directory in the archive but there is no corresponding filesystem representation for that directory.

You will probably not need to do this in your code. One of the only times you will want to do this is if you want an empty directory in the zip archive. The reason: if you add a file to a zip archive that is stored within a multi-level directory, all of the directory tree is implicitly created in the zip archive.