C# Patterns

This file extends common/patterns.md with C#-specific content.

API Response Pattern

csharp

public sealed record ApiResponse<T>(
    bool Success,
    T? Data = default,
    string? Error = null,
    object? Meta = null);

Repository Pattern

csharp

public interface IRepository<T>
{
    Task<IReadOnlyList<T>> FindAllAsync(CancellationToken cancellationToken);
    Task<T?> FindByIdAsync(Guid id, CancellationToken cancellationToken);
    Task<T> CreateAsync(T entity, CancellationToken cancellationToken);
    Task<T> UpdateAsync(T entity, CancellationToken cancellationToken);
    Task DeleteAsync(Guid id, CancellationToken cancellationToken);
}

Options Pattern

Use strongly typed options for config instead of reading raw strings throughout the codebase.

csharp

public sealed class PaymentsOptions
{
    public const string SectionName = "Payments";
    public required string BaseUrl { get; init; }
    public required string ApiKeySecretName { get; init; }
}

Dependency Injection

Depend on interfaces at service boundaries
Keep constructors focused; if a service needs too many dependencies, split responsibilities
Register lifetimes intentionally: singleton for stateless/shared services, scoped for request data, transient for lightweight pure workers