Why strings behave like ValueType

Question

I was perplexed after executing this piece of code, where strings seems to behave as if they are value types. I am wondering whether the assignment operator is operating on

Answer 1

They don't. You changed the pointer of a2, not the object it pointed to.
When you are using classes and getting your expected behavior, you must be setting a property of the object, not its reference.

Any other class will behave the same:

Foo a = new Foo(1);
Foo b = a; //a, b point to the same object

b.Value = 4; // change property
Assert.Equals(a.Value, 4); //true - changed for a

b = new Foo(600); // new reference for b
Assert.Equals(a.Value, 4); //true
Assert.Equals(b.Value, 600); //true