Web Api2 Get Path Current Project

I am developing an Web Api2 Solution. It has a main Project, and other projects.

My main Project is in path

C:/Prj/mainProj

Other Project is in path

C:/Prj/Services

From the main Controller in main Project, I call a method in Services Project, where I need to read a file that is under Services directory.

I am using

AppDomain.CurrentDomain.BaseDirectory;

or

System.Web.HttpRuntime.AppDomainAppPath;

but it retrieves main Project path (C:/Prj/mainProj)

how can i retrieve current Project path?

C:/Prj/Services