Coding Best Practices  

Mastering C# Coding Standards: Best Practices for Clean and Maintainable Code

Writing clean, readable, and maintainable code is essential for long-term success in any software project. For developers working with C#, following consistent coding standards not only improves collaboration but also reduces bugs, enhances readability, and ensures scalability.

coding-standards

This article covers the most widely accepted C# coding standards and best practices that every .NET developer should follow.

1. Naming Conventions

1.1 PascalCase

Used for:

  • Class names

  • Methods

  • Properties

  • Namespaces

public class CustomerService
{
    public void ProcessOrder() { }
    public string CustomerName { get; set; }
}

1.2 camelCase

Used for:

  • Local variables

  • Private fields (optionally prefixed with _)

  • Method parameters

private int _orderCount;

public void AddCustomer(string customerName)
{
    int totalOrders = 0;
}

1.3 UPPER_CASE

Used for:

  • Constants

public const int MAX_RETRY_COUNT = 3;

2. Commenting and Documentation

2.1 XML Comments

Use XML comments for methods, classes, and public APIs.

/// <summary>
/// Calculates the total price including tax.
/// </summary>
/// <param name="amount">Base amount.</param>
/// <param name="tax">Tax percentage.</param>
/// <returns>Total price with tax included.</returns>
public decimal CalculatePrice(decimal amount, decimal tax) { }

2.2 Inline Comments

Use inline comments only when logic is not easily readable.

3. Coding Style Guidelines

3.1 Use var Wisely

Use var when the type is obvious.

✔ Good

var customer = new Customer();

✘ Bad

var result = GetData(); // unclear type

3.2 One Class per File

Keep file organization clean.

3.3 Keep Methods Short

Each method should ideally do one task.

4. Error Handling Practices

4.1 Use Try-Catch Only for Exceptional Cases

Avoid writing empty catch blocks.

try
{
    SaveFile();
}
catch (IOException ex)
{
    _logger.LogError(ex, "File saving failed");
}

4.2 Throw Meaningful Exceptions

throw new ArgumentNullException(nameof(customerId));

5. SOLID Principles Overview

S — Single Responsibility Principle

A class should have one reason to change.

O — Open/Closed Principle

Code should be open for extension, closed for modification.

L — Liskov Substitution Principle

Child classes should not break parent behavior.

I — Interface Segregation Principle

Prefer small, specific interfaces.

D — Dependency Inversion Principle

Depend on abstractions, not concrete classes.

6. Use Async Programming Properly

Use async/await for non-blocking IO operations.

public async Task<List<Customer>> GetCustomersAsync()
{
    return await _dbContext.Customers.ToListAsync();
}

Avoid using .Result and .Wait() as they may cause deadlocks.

7. Avoid Hardcoding Values

Use configuration or constants instead.

✔ Good

var apiUrl = _config["ApiSettings:BaseUrl"];

✘ Bad

var apiUrl = "https://example.com/api";

8. Organize Your Project Structure

A clean folder structure improves maintainability:

/Controllers
/Services
/Repositories
/Models
/DTOs
/Interfaces

9. Use Dependency Injection

Built-in DI in .NET promotes cleaner architecture.

services.AddScoped<ICustomerService, CustomerService>();

10. Write Unit Tests

Good coding standards include testing.

  • Use naming pattern: MethodName_State_ExpectedResult

  • Test both success and failure scenarios.

[TestMethod]
public void AddOrder_ValidOrder_ShouldReturnTrue()
{
    // Arrange
    // Act
    // Assert
}

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