Is it possible for unity to open visual studio as a dumb text editor?

We just started using a project structure that Unity doesn't understand, and I would rather it just not try to screw with our project file. Is there any way to tell it to open visual studio as a regular text editor, rather than magically creating an sln and csproj? As if I wanted to say "edit source files with notepad" except "notepad" happened to be "visual studio". It is being too smart for its own good.