C# Value and Reference types

Question

Please see the following lines of code mentioned below:

byte[] a = { 1, 2, 3, 4 };
byte[] b = a; // b will have all values of a.
a = null; 

Answer 1

Your question makes the assumption that when you make the assignment:

byte[] b = a;

And that you're making some sort of graph association like so:

b -> a -> { 1, 2, 3, 4 }

And when you make the assignment of a to null, you impact the value of b, because:

b -> a -> null

But that's not how copying references work. When you copy the reference, you really make a copy of the reference that a has, like so:

a ----> { 1, 2, 3, 4 }
              ^
b ------------|

This is why when you make the assignment of a to null, you don't impact the value of b, just a:

a ----> null      { 1, 2, 3, 4 }
                          ^
b ------------------------|