retriving php variable in c#
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i've my php file for download some file.
if i run this file in a webpage i get automaticalli savedialog with correct filename and extension.

Now i've my application written in c#.How to obtain fileneme and extension in this application?
 i think have to read php variable,but i didn't say what are correct way to read it.
php var to read are `"$file"` and `"$ext".`

I've read some article here,but i'm confused.
Some user speak about webclient,other speak about httpwebrequest.
Can put me in correct way?