asp.net 2.0 gridview and hyperlink field

[salloum]

Hi
I'm doing a project using visual studio 2005 and ASP.net 2.0
My database contains a table with a field which contains file names of files existing in a folder named "files" in the "App_data" Folder.
I have a hyperlink field in the gridview to link to these files.
What value do I have to assign to DataNavigateUrlFields and DataNavigateUrlFormatString to access these files.
Notice that I tried to write the value "~/App_Data/"+Filename in the database column FileName and passed this value to DataNavigateUrlFields and it didn't work...
plz help

[Banfa]

a folder named "files" in the "App_data" Folder.

I tried to write the value "~/App_Data/"+Filename in the database column

Without any knowledge of your system

App_data != App_Data for most web applications

I folder named "files" in App_data so

"~/App_data/files/"+Filename