How to edit any .cs file from my C# application?

I want to replace all the private modifiers to public modifiers, in any given .cs file, using C# application.

Aji Jose

Thank you Nilsson.

Actually I want to write testcases in NUnit, for my UI (Forms). And I can't found a way for testing UI with NUnit. Please correct me, if there is a way.
nlhowell
Why would you want that

anyway here is something you can do (although I dont recomennd it)

StreamReader r = new SreamReader("myapp.cs");
string text = r.ReadToEnd().Replace("private", "public");
r.Close();

StreamWriter w = new StreamWriter("myapp.cs");
w.Write(text);
w.Flush();
w.Close();
How to edit any .cs file from my C# application?