How to make a valid Windows filename from an arbitrary string?

Question

I\'ve got a string like \"Foo: Bar\" that I want to use as a filename, but on Windows the \":\" char isn\'t allowed in a filename.

Is there a method that will turn \

Answer 1

A simple one line code:

var validFileName = Path.GetInvalidFileNameChars().Aggregate(fileName, (f, c) => f.Replace(c, '_'));

You can wrap it in an extension method if you want to reuse it.

public static string ToValidFileName(this string fileName) => Path.GetInvalidFileNameChars().Aggregate(fileName, (f, c) => f.Replace(c, '_'));