How to make forward-word, backward-word, treat underscore as part of a word?

Question

In my C# mode, M-b and M-f are bound to {backward,forward}-word.

But these things stop at underscores, which I use sometimes as a prefix on member variables.

Answer 1

You don't necessarily have to modify your syntax table. _ belongs to the syntax class symbol in csharp-mode, so you may use forward-symbol instead of forward-word. forward-symbol is in thingatpt, which comes with emacs (at least 23).

You can btw quickly look at the syntax table of a mode with C-h s (describe-syntax).