csharp-code-style

C# Code Style Guide

Overview

C# 코딩 표준 (POCU 기반, C# 9.0 기준)

Core Topics:

명명 규칙 (m접두어, b접두어, E/S접두어)
코드 작성 규칙
클래스 구조 순서
C# 9.0 패턴

Language Note

이 문서는 한국어를 기본으로 작성되었으며, 코드 예제와 기술 용어는 영어를 사용합니다. 섹션 제목은 영어로 통일하고, 설명과 주석은 한국어로 작성합니다.

섹션 제목: 영어 (Naming Conventions, Code Writing Rules 등)
설명/주석: 한국어
코드 예제: 영어 (변수명, 클래스명, 코드 코멘트)
표(Table) 헤더: 영어, 내용은 영어 또는 한국어 혼용 가능

Naming Conventions

Quick Reference

Element Convention Example

Class PascalCase PlayerManager , OrderService

Struct SPascalCase SUserID , SPlayerData

Interface IPascalCase IDisposable , IOrderService

Enum EPascalCase EDirection , EOrderStatus

Method (public) PascalCase (동사+명사) GetAge() , ProcessOrder()

Method (private) camelCase getAge() , processOrder()

Property PascalCase Name , OrderID

Private Field mPascalCase mAge , mOrderRepository

Local Variable camelCase totalAmount , isValid

Parameter camelCase customerId , orderDate

Constant ALL_CAPS MAX_RETRY_COUNT , DEFAULT_TIMEOUT

Static readonly ALL_CAPS MY_CONST_OBJECT

Boolean Variable bCamelCase / mbPascalCase bFired , mbIsEnabled

Boolean Property Is/Has/Can/Should IsFired , HasChildren

Private Member Pattern

public class OrderService { // Private fields: m + PascalCase private readonly IOrderRepository mOrderRepository; private readonly ILogger mLogger; private int mRetryCount; private bool mbIsProcessing; // boolean: mb prefix

// Constructor parameter: camelCase (no prefix)
public OrderService(IOrderRepository orderRepository, ILogger logger)
{
    mOrderRepository = orderRepository;
    mLogger = logger;
}

// Public method: PascalCase
public Order GetOrder(int orderId)
{
    return getOrderInternal(orderId);
}

// Private method: camelCase
private Order getOrderInternal(int orderId)
{
    return mOrderRepository.Find(orderId);
}

}

Enum and Struct Prefixes

// Enum: E prefix public enum EDirection { None, North, South, East, West }

// Bit flags enum: Flags suffix [Flags] public enum EVisibilityFlags { None = 0, Visible = 1, Hidden = 2, Collapsed = 4 }

// Struct: S prefix (readonly struct는 제외 가능) public struct SUserID { public int Value { get; } }

// readonly record struct: S prefix 불필요 public readonly record struct UserID(int Value);

Nullable Naming

// Nullable parameter: OrNull suffix public Animation GetAnimation(string nameOrNull) { if (nameOrNull == null) { return DefaultAnimation; } return mAnimations[nameOrNull]; }

// Nullable return: OrNull suffix public string GetNameOrNull() { return mbHasName ? mName : null; }

// Recursive function: Recursive suffix public int FibonacciRecursive(int n) { if (n <= 1) { return n; } return FibonacciRecursive(n - 1) + FibonacciRecursive(n - 2); }

Code Writing Rules

Prohibited Patterns

// [WRONG] var keyword var order = GetOrder(1); var items = new List<Item>();

// [CORRECT] Explicit type Order order = GetOrder(1); List<Item> items = new List<Item>();

// [WRONG] Null coalescing operator (??) string name = inputName ?? "Default";

// [CORRECT] Explicit null check string name; if (inputName != null) { name = inputName; } else { name = "Default"; }

// [WRONG] using declaration (C# 8.0) using FileStream stream = new FileStream(path, FileMode.Open);

// [CORRECT] using statement using (FileStream stream = new FileStream(path, FileMode.Open)) { // ... }

// [WRONG] target-typed new() List<Order> orders = new();

// [CORRECT] Explicit type List<Order> orders = new List<Order>();

// [WRONG] Async suffix public async Task<Order> GetOrderAsync(int id);

// [CORRECT] No Async suffix public async Task<Order> GetOrder(int id);

// [WRONG] inline out declaration if (int.TryParse(input, out int result))

// [CORRECT] separate out declaration int result; if (int.TryParse(input, out result))

Required Patterns

// Always use braces, even for single line if (condition) { DoSomething(); }

// Float literals with f suffix float value = 0.5f; float another = 1.0f;

// Switch must have default case switch (status) { case EStatus.Active: Process(); break; case EStatus.Inactive: Skip(); break; default: Debug.Fail("Unknown status"); break; }

// Debug.Assert for all assumptions Debug.Assert(order != null, "Order should not be null"); Debug.Assert(count > 0, "Count must be positive");

// Properties instead of getter/setter methods // [WRONG] public int GetAge() { return mAge; } public void SetAge(int age) { mAge = age; }

// [CORRECT] (.NET 5+ only - NOT available in Unity) public int Age { get; private init; }

// [CORRECT] (Unity compatible) public int Age { get; private set; }

C# 9.0 Patterns

Unity Limitation: init accessor is NOT available in Unity (requires .NET 5+ runtime). See Modern Patterns Reference for details and alternatives.

// private init (C# 9.0) - .NET 5+ only, NOT available in Unity public class Customer { public string Name { get; private init; } // Use 'private set' in Unity public string Email { get; private init; } }

// Record for immutable data public record OrderDto(int Id, string CustomerName, decimal TotalAmount);

// Pattern matching switch expression (available in Unity) public string GetStatusMessage(EOrderStatus status) { return status switch { EOrderStatus.Pending => "Order is pending", EOrderStatus.Completed => "Order completed", _ => throw new ArgumentOutOfRangeException(nameof(status)) }; }

Class Structure Order

public class OrderService : IOrderService { // 1. Constants private const int MAX_RETRY_COUNT = 3; public static readonly TimeSpan DEFAULT_TIMEOUT = TimeSpan.FromSeconds(30);

// 2. Private member variables
private readonly IOrderRepository mOrderRepository;
private readonly ILogger mLogger;
private int mProcessedCount;
private bool mbIsInitialized;

// 3. Properties (with private member above if needed)
public int ProcessedCount => mProcessedCount;
public bool IsInitialized => mbIsInitialized;

// 4. Constructors
public OrderService(IOrderRepository orderRepository, ILogger logger)
{
    mOrderRepository = orderRepository;
    mLogger = logger;
}

// 5. Public methods
public Order GetOrder(int id)
{
    Debug.Assert(id > 0, "ID must be positive");
    return mOrderRepository.Find(id);
}

public void ProcessOrder(Order order)
{
    validateOrder(order);
    processInternal(order);
}

// 6. Private methods
private void validateOrder(Order order)
{
    Debug.Assert(order != null);
}

private void processInternal(Order order)
{
    // Implementation
}

}

File Organization

각 클래스는 독립된 파일에 작성
파일명 = 클래스명 (정확히 일치)
Partial 클래스: ClassName.SubName.cs

Reference Documentation

Naming Conventions

Complete naming rules:

m/mb 접두어 상세
E/S 접두어 규칙
OrNull 접미어 패턴
ALL_CAPS 상수 규칙

Modern Patterns

C# 9.0 language features:

Records and init-only properties
Pattern matching
File-scoped namespaces (C# 10)
금지 패턴 상세

Error Handling

Error handling patterns:

Debug.Assert 사용
경계에서만 예외 처리
null 반환/매개변수 회피
유효성 검증 패턴

Key Principles

가독성 최우선: 명확하고 이해하기 쉬운 코드 작성
명시적 타입: var 사용 금지, 타입 명시
Null 안전: OrNull 접미어로 nullable 명시
Assertion: 모든 가정에 Debug.Assert 사용
경계 검증: 외부 데이터는 경계에서만 검증
Use init: Prefer C# 9.0 private init (.NET 5+ only, NOT available in Unity)
No Emoji: 코드 예제 및 문서에서 이모지 사용 금지, 텍스트 태그 사용 ([WRONG], [CORRECT], [CAUTION])

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