http url for local files asp.net

http url for local files asp.net

I have a treeveiw for a folder under my application folder. I would like
to provide links to the files in the folder. The folder might have sub
folders and so on. How can I provide http urls in the links.
When I do this I only get the physical location of the file instead of the
http url. Path.Combine(file.DirectoryName, file.Name)
Thanks.