Embracing Records in C#: The Pros and Cons

As a software developer, I am always interested in new features getting added to my language of choice (C#) and how it can help me improve my day to day life as a developer.  I don’t really talk much about this sort of thing outside of giving presentations and stuff to the dev teams at my work, but I would like to start sharing more of my thoughts and experiences as a developer on GGN so lets see how this goes!

C# continues to evolve rapidly with every new version, bringing exciting features to improve development productivity, code readability, and maintainability. One of the noteworthy additions in C# 9.0 was the record type. In this post, we’ll explore what records are, why you should consider using them, and situations where they might not be the ideal choice.

Understanding Records in C#

At a high level, a record is a type that is used to define immutable reference data types. It creates an immutable object, meaning once a record object is created, it cannot be changed. Any modification to a record object results in a new record object.

Here’s a simple example:

public record Person(string Name, int Age);

This defines a Person record with a Name and an Age. You can create an instance of Person like so:

var john = new Person("John Doe", 30);

Why Choose Records?

There are several reasons why you might want to choose records for your C# development:

1. Immutability by Default

Immutability brings a lot of advantages. Immutable objects are inherently thread-safe, they can make your code easier to reason about, and they help prevent certain classes of bugs related to state changes. If you have ever faced bugs due to accidental mutation of an object (like I just spent several days trying to figure out last week), you’ll appreciate records.

2. Value Semantics for Equality

Records provide value-based equality semantics, unlike classes which follow reference-based semantics. In simple terms, two record instances are equal if their properties are equal.

var john1 = new Person("John Doe", 30);
var john2 = new Person("John Doe", 30);
Console.WriteLine(john1 == john2); // Output: True

3. Built-In Copy and Clone

Records support the with keyword which provides a simple syntax for non-destructive mutation, creating a new record by copying an existing one and changing some of the values:

var jane = john with { Name = "Jane Doe" };

4. Concise Syntax with Init-Only Properties

Records introduce a compact way to declare types. The positional syntax can be used to simplify property declaration and assignment. This reduces the boilerplate code in your codebase.

When are Records Not Ideal?

Despite the numerous advantages, records may not always be the best choice:

1. For Mutable Data

Since records are immutable, they’re not a good fit for objects that need to change their state over time.

2. Performance Considerations

Records come with built-in features like value-based equality checks and copies which, while convenient, have performance implications. These operations can be costly, especially for larger records.

3. Interoperability

If your C# code is used by other .NET languages that do not support records, or if your project targets an older .NET framework version (older than .NET 5), then records might not be a suitable choice.

In conclusion, records in C# are a powerful tool for creating immutable data models, reducing boilerplate code, and improving the robustness of your software. However, they may not be ideal for all scenarios, and developers should be mindful of their performance implications and requirements for mutable data. As always, the right tool should be chosen based on the specific needs of your project.  If you want to go more in-depth on Records in C#, I highly suggest checking out the official documentation which is great!

And if you are looking for more ways to up your game as a .NET developer, I highly suggest you check out my post on using Visual Studio Live Share.





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