Are structs within classes passed as value?

Question

I have:

A struct

struct Data { int a; int b; }

A class containing the struct

class Packet {
    Data DataStruct;
}

When I now instantiate my class, I assume that the struct lives on the heap. If I now do something like

SomeClass.Process(new Packet().DataStruct);
SomeClass.Process(new Packet().DataStruct.a);

will it be passed as value?

If not, is there any reason not to make the struct into a class instead?

Answer 1

structs are value types, so it will be passed as value. Classes are reference types.

Everything will be passed as value unless out or ref is specified.

Answer 2

A struct is always passed by value. In other words, a copy of it is created and provided to the called function.

While the struct is allocated on the heap, its actually part of the class its contained by rather than as a separate entity.