Class vs Record in C#

In C#, both classes and records are used to represent complex data structures, but they have distinct purposes, features, and usage patterns. Below is a comparison between them:

1. Class in C#

Overview

• A class is a reference type that represents an object with properties, fields, and methods.
• It allows both mutability (ability to change object state) and encapsulation (hiding internal state).

Key Features

• Supports inheritance and polymorphism.
• Encapsulates behavior using methods and fields.
• State can change over time (mutable).
• Two objects of the same class with identical values are not equal unless you override the equality members (like Equals and GetHashCode).

Example of a Class:

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }

    public override string ToString() => $"Name: {Name}, Age: {Age}";
}

When to Use?

• When the focus is on behavior along with data.
• When you need inheritance and polymorphism.
• When the object’s state will change frequently.

2. Record in C# (Introduced in C# 9.0)

Overview

• A record is a special type of class optimized for immutable data.
• It is typically used to represent data models where the data does not change after initialization (although mutable records are allowed).

Key Features

• Records are reference types like classes.
• Automatically generates value-based equality (==, Equals, GetHashCode).
• Supports deconstruction into individual components.
• The primary intent is immutable data structures (by default).

Example of a Record:

public record Person(string Name, int Age);

With a record, two instances with the same values will be treated as equal:

var person1 = new Person("Alice", 30);
var person2 = new Person("Alice", 30);

Console.WriteLine(person1 == person2); // True

When to Use?

• When the focus is primarily on data rather than behavior.
• When immutable objects are preferred.
• For data transfer objects (DTOs) or state snapshots.

3. Class vs Record Comparison Table

4. Record Class and Record Struct

• Record Class: By default, a record is a class (reference type).
• Record Struct: Introduced in C# 10, it is a value type version of records for scenarios where copying data is more efficient.

Example of Record Struct:

public record struct Point(int X, int Y);

5. Conclusion

• Use classes when you need mutable objects, inheritance, or objects with behavior.
• Use records when you want immutable, value-based objects primarily used to hold data (like DTOs). Records simplify code where equality and immutability are important.