What reference data types are implemented in C#?

In C#, reference data types are types that are stored in the managed heap, and variables of such types contain a reference to an object, not the object itself. The main reference types in C#:

• class — classes, for example string, user-defined classes.
• interface — interfaces.
• delegate — delegates that represent methods.
• array — arrays, for example int[].
• string — a string, although it looks like a primitive, it is a reference type.

Example:

class Person {
    public string Name;
}

Person p1 = new Person();
p1.Name = "Ivan";
Person p2 = p1; // p2 and p1 refer to the same object
p2.Name = "Peter";
Console.WriteLine(p1.Name); // Will output "Peter"

It is evident that when assigning reference type variables, the reference is copied, not the object itself.