Immutable Classes in C#: Why and How to Use Them for Safer 💻Code

In C#, an immutable class is a class whose objects cannot be modified once created. Once you set the values of an object’s properties or fields in an immutable class, they cannot be changed, ensuring that the state of the object remains constant.

This concept is particularly useful in multithreaded programming and helps prevent unintended side effects since no changes can be made to an object’s state after it is constructed.

Key Characteristics of Immutable Classes

1. Readonly Fields: Fields are often marked as readonly to prevent modification after initialization.
2. No Setters: Properties are usually defined with only get accessors, and there are no set accessors.
3. Private Constructors: If using factory methods to create instances, constructors can be private.
4. Value Types and Immutable Reference Types: If fields are reference types, they should also be immutable to ensure the whole object remains immutable.

How to Create an Immutable Class in C#

Here’s a basic example of an immutable class in C#: