asp.net 2005 treeview control

I'm trying to list files from on my directories using treeview control.
when user drills down to files under directories, I want them to open
the file when they clicked on the file.

I know I can do this in regular html like this
<a href="C:\myfolder\myfile.pdf">MyFile</a>
when I click on the MyFile link in regular html, the pdf file opens in
pdf reader.

Is there any way I can do this using treeview control? I tried using
navigateurl on the node. But it only works when you give web url, not
the file url.