C# Value Types, Reference Types, and Object Semantics

It is easy to describe class and struct as “heap versus stack,” but that explanation is incomplete. The more important distinction is semantic.

A value type represents a value: a coordinate, amount, range, or color. A reference type represents an object with identity: an order, user, connection, or service instance.

Three Differences

• Storage: value types are often stored inline with their owner, while reference variables point to objects.
• Copy semantics: assigning a value type copies the value; assigning a reference type shares the object reference.
• Lifetime: reference objects are usually managed by GC; value types often live with their owner or stack frame.

Choosing Between Them

Use value types for small, immutable, identity-free data. Use reference types when identity, state changes, inheritance, or sharing matter.