How to Get a File Path in a Specific Project in a Web Application Solution?

I'm writing a Visual Studio Macro and need to read a XML file in my project and write something. i can't get the correct file path! in 开发者_JAVA技巧my web application solution i have to projects for business and UI files. and my xml file named fa.xml located on UI project in a separate folder. i want to use this macro for many solutions. but the structure is the same.

How can I get the Path of a file in a specific project in my solution?

OK, I'm just going to check for the file. You should get the general idea:

If my.computer.filesystem.fileexists(application.startuppath + "\blabla\fa.xml") then
  ...
end if