Clean Code in C#: How to Write Code You Won't Be Ashamed to Show Colleagues

Introduction: Why Clean Code Is Not About Aesthetics, But About Money

Imagine you start a new job, open a C# project, and see a method that is 500 lines long, variables like a, b, temp, and comments written in a mix of Russian and English. Sound familiar? It probably does. Such code works, but maintaining it becomes a nightmare. Clean code in C# is not a perfectionist's whim, but a tool that saves the team hours, nerves, and money.

In this article, we won't lecture you. Instead, we'll break down specific techniques that will help you write C# code that is understandable to a beginner and pleasing to an experienced developer. Let's go!

1. Names Matter: How to Name Variables, Methods, and Classes

The simplest way to make code cleaner is to use meaningful names. C# is case-sensitive, but that's no excuse for int x or string d.

Variables: Say What You Store

Bad:

int d; // what is this? date? distance? money?string n; // name? number? notebook?

Good:

int daysUntilDeadline;string userName;

The rule is simple: if you can't understand what a variable stores without a comment after a month, the name is bad. Avoid abbreviations like usr or cnt — they save a second when typing but cost minutes when reading.

Methods: Verb + Noun

A method is an action. Name it so it's clear what it does:

• CalculateTotalPrice() — calculates the total price;
• SendEmailNotification() — sends a notification;
• ValidateUserInput() — validates user input.

Bad example: ProcessData() — too abstract. What does "process" mean? Delete? Transform? Save?

Classes: Singular or Plural Nouns

A class is an entity. User, Order, PaymentProcessor. Avoid suffixes like Manager or Helper unless justified by the architecture. Often, such classes become a "dump" for everything.

2. Methods Should Be Small and Do One Thing

The golden rule of clean code: a method should solve one task and solve it well. If a method takes more than 20–30 lines, it probably needs to be broken down.

Example: Refactoring a Monster

Imagine a method that registers a user:

public void RegisterUser(string name, string email){    // validation    if (string.IsNullOrWhiteSpace(name)) throw new ArgumentException();    if (!email.Contains("@")) throw new ArgumentException();    // saving to DB    using var db = new AppDbContext();    var user = new User { Name = name, Email = email };    db.Users.Add(user);    db.SaveChanges();    // sending email    var smtp = new SmtpClient();    smtp.Send("admin@site.com", email, "Welcome", "Hello!");}

What's wrong here? Three responsibilities: validation, database work, sending email. If the sending logic changes, you'll have to touch the registration method. Let's break it down:

public void RegisterUser(string name, string email){    ValidateUser(name, email);    var user = CreateUser(name, email);    SaveUser(user);    SendWelcomeEmail(email);}

private void ValidateUser(string name, string email){    if (string.IsNullOrWhiteSpace(name))         throw new ArgumentException("Name is required", nameof(name));    if (!email.Contains("@"))         throw new ArgumentException("Invalid email", nameof(email));}

private User CreateUser(string name, string email){    return new User { Name = name, Email = email };}

private void SaveUser(User user){    using var db = new AppDbContext();    db.Users.Add(user);    db.SaveCh