dotnet-patterns

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---
name: dotnet-patterns
description: 惯用的C#和.NET模式、约定、依赖注入、async/await以及构建健壮、可维护的.NET应用程序的最佳实践。
origin: ECC
---

# .NET 开发模式

用于构建健壮、高性能且可维护应用程序的惯用 C# 和 .NET 模式。

## 何时激活

* 编写新的 C# 代码时
* 审查 C# 代码时
* 重构现有 .NET 应用程序时
* 使用 ASP.NET Core 设计服务架构时

## 核心原则

### 1. 优先使用不可变性

对数据模型使用记录和仅初始化属性。可变性应作为明确且有理由的选择。

```csharp
// Good: Immutable value object
public sealed record Money(decimal Amount, string Currency);

// Good: Immutable DTO with init setters
public sealed class CreateOrderRequest
{
    public required string CustomerId { get; init; }
    public required IReadOnlyList<OrderItem> Items { get; init; }
}

// Bad: Mutable model with public setters
public class Order
{
    public string CustomerId { get; set; }
    public List<OrderItem> Items { get; set; }
}
```

### 2. 显式优于隐式

明确表达可空性、访问修饰符和意图。

```csharp
// Good: Explicit access modifiers and nullability
public sealed class UserService
{
    private readonly IUserRepository _repository;
    private readonly ILogger<UserService> _logger;

    public UserService(IUserRepository repository, ILogger<UserService> logger)
    {
        _repository = repository ?? throw new ArgumentNullException(nameof(repository));
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    public async Task<User?> FindByIdAsync(Guid id, CancellationToken cancellationToken)
    {
        return await _repository.FindByIdAsync(id, cancellationToken);
    }
}
```

### 3. 依赖抽象

对服务边界使用接口。通过依赖注入容器注册。

```csharp
// Good: Interface-based dependency
public interface IOrderRepository
{
    Task<Order?> FindByIdAsync(Guid id, CancellationToken cancellationToken);
    Task<IReadOnlyList<Order>> FindByCustomerAsync(string customerId, CancellationToken cancellationToken);
    Task AddAsync(Order order, CancellationToken cancellationToken);
}

// Registration
builder.Services.AddScoped<IOrderRepository, SqlOrderRepository>();
```

## 异步/等待模式

### 正确使用异步

```csharp
// Good: Async all the way, with CancellationToken
public a

Use this skill

{
  "model": "gpt-4o-mini",
  "skill": "imp-a73b2e31-ca88-4d18-b9cf-6c535725257d",
  "messages": [{ "role": "user", "content": "…" }]
}

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