Check if a variable is in an ad-hoc list of values

Question

Is there a shorter way of writing something like this:

if(x==1 || x==2 || x==3) // do something

Wha

Answer 1

public static bool In(this T x, params T[] set)
{
    return set.Contains(x);
}

...

if (x.In(1, 2, 3)) 
{ ... }

Required reading: MSDN Extension methods