C# find reference of a class in a directory of .cs files

I want to create a method that simulates the VS "Find All References" function. First I'll detail exactly what I will use this for, and then I'll make it a more broad question.

I want to use this method in Unity3D to basically find any script that isn't being referenced in any other script.

I have a folder with .cs files, and the name of those files correspond to the C# class that's inside the file.

Then for each class(file) I want to search if there's a reference of it on the rest of the files.

Is there a straightforward way of doing this? Or should I just try to parse the files?