C# Linq intersect/except with one part of object

Question

I\'ve got a class:

class ThisClass
{
  private string a {get; set;}
  private string b {get; set;}
}

I would like to use the Intersect and

Answer 1

Maybe

// returns list of intersecting property 'a' values
foo.Select(f => f.a).Intersect(bar.Select(b => b.a));

BTW property a should be public.