Question

I have a list of class A, class A contains a list of class B. I want to operate on all instances of B within all instances of class A.

var myListOfA = new List<A>();

class A
{
    public List<B> ListOfB;
}

How can I iterate over all B i.e. foreach(var b in myListOfA.ListOfB){}?

Answer 1

You can use SelectMany:

foreach(var b in myListOfA.SelectMany(a => a.ListofB))

See it in action at ideone.com.