Explicit casting

You've worked out the answer correctly :)

It would also have worked if, although A didn't inherit from B, there was a user-defiined implicit conversion from A to B and an explicit conversion from B to A:

using System;




class B
{
 public string Name {get; set;}


 public B(A a)
 {
       Name = a.Name;
 }    
}




class A
{
 public string Name {get; set;}


 public static implicit operator B(A a)
 {
     return new B(a);
 }


 public static explicit operator A(B b)
 {
    A a = new A();
    a.Name = b.Name;
    return a;
 }
}


class Test
{
 static void Main()
 {
   A a = new A();
   a.Name = "Neos";
   B b = a;
   Console.WriteLine(b.Name);
   A aa = (A)b;
   Console.WriteLine(aa.Name);
   Console.ReadKey();
 }
}

However, you'd only do this if there was a strong relationship between A and B falling short of inheritance. My example is, of course, artificial.

For instance, you have this sort of thing between the 'int' and 'long' types though these are structs and so not capable of an inheritance relationship in any case.