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

Maybe when you have a struct (which is a value type):

struct Foo
{
    int i;

    public void Test()
    {
        i++;
    }
}

static void update(ref Foo foo)
{
    foo.Test();
}

and

Foo b = new Foo();
update(ref b);

Here you would to use two-parameters with out like:

static void update(Foo foo, out Foo outFoo) //Yes I know you could return one foo instead of a out but look below
{
    foo.Test();

    outFoo = foo;
}

imaging the method having more than one Foo then you would get twice the parameters with out versus ref. An alternative is to return a N-tuple. I don't have a real-world example on when to use this stuff.

Add on: Different .TryParse methods could also have avoided out if they returned Nullable instead which essentially is a tuple of boolean * T.