Determines filename where message is stored.

A String value.  

object.Filename [= value]

The Filename Property syntax has these parts:

Pop3 server and message objects store all information in files on disk. If you specify Filename property for the message, Pop3 server will read specified file and send it's contents to remote user when message body is requested. If you don't specify filename, message body will not be visible to connected user and it's size will be 0.

However, if you want to generate message on the fly (for instance, if you have some important information or just want to send advertisements to users), you can leave this field empty and store data directly to Body property. If you do so, Pop3 server will create new temporary file that will be valid as long as message object exists, and will write to it. You don't have to manually delete such file because Pop3 server will do that for you.

If your message is not the only one in a given Filename, in other words if file is mailbox, you should specify StartPosition and EndPosition of the message in the given mailbox.