is there a way to determine which project a file belongs? programmatically...

Question

My Solution contains a lot of projects, and i have this another application which downloads the latest files from the solution, now from those files, i want to know what project they came from so i could get the assemblyinfo.cs of the affected project file and modify/increment it programatically..
This should have nothing to do with TFS team build or something like that... well TFS API maybe, but i would like to keep this question simple and stick to plain old c#, thanks!