References specific user based on his UID.

A FtpUser object.  Reference to requested user in the collection.

object.UIDs(UserUID)

The UIDs Property syntax has these parts:

Unlike Item property that uses relative indexes, UIDs property will return reference to some user based on his unique ID - unique value he got when he connected. ID for the user will not be changed during client's connection, and no two users will have the same ID as long as the server is started.

You can freely store user's ID in your program and access the reference to the user later on, from any function - of course, assuming the client doesn't disconnect in the meantime.