When is using the C# ref keyword ever a good idea?

Question

The more I see ref used in production code, the more misuse I encounter and the more pain it causes me. I have come to hate this keyword, because from a framework-building s

Answer 1

I try to avoid it on public APIs, but it definitely has uses. Mutable value-types is an important one, especially on things like CF (where mutable structs are more common, due to platform requirements). However, perhaps the most common time I use it is when refactoring parts of a complex algorithm out into a few methods, where a state object is overkill and I need to pass multiple values around:

i.e.

var x = .....
var y = .....
// some local code...
var z = DoSomethingSpecific(ref x, ref y); // needs and updates x/y
// more local code...

etc. Where DoSomethingSpecific is a private method, just moved out to keep method responsibility manageable.