I've added a bunch of files from my older project into my new project. They're still not playing an active role in my current code and there are missing classes that won't make them fully functional anyway, I just want them there so I can gradually rework each file to be compatible with my newest code. Is there a way tell the compiler not to pay attention to these C# files and report errors?
P.S: I'm using SharpDevelop
Although it is possible to give specific compiler instruction, I'd remove the files from the solution and put them somewhere safe in version control.
Having these files in the solution can easily be confusing when browsing the sources; I would not expect to have to check the BuildAction property of C# files to find out whether or not I am looking at something that is part of the build.
I read a lot of code in a source control viewer (looking a delta's and history), compiler options are not very obvious in environments like these.
Put them safe in source control and remove them from the build.