# 查看已安裝版本
dotnet --list-sdks

# 全局設置默認版本
dotnet new globaljson --sdk-version 8.0.301

{
  "configurations": [
    {
      "name": ".NET Core Launch (web)",
      "type": "coreclr",
      "request": "launch",
      "preLaunchTask": "build",
      "program": "${workspaceFolder}/bin/Debug/net8.0/YourProject.dll",
      "args": [],
      "cwd": "${workspaceFolder}",
      "stopAtEntry": false,
      "serverReadyAction": {
        "action": "openExternally",
        "pattern": "\\bNow listening on:\\s+(https?://\\S+)"
      }
    }
  ]
}

創(chuàng)建一個ASP.NET Core Web API項目，包含以下功能：
- 使用Entity Framework Core + SQLite
- 包含Book模型（Id:int, Title:string, Author:string, ISBN:string）
- 包含BooksController的CRUD端點
- 啟用Swagger

builder.Services.AddDbContext<AppDbContext>(options => 
    options.UseSqlite(builder.Configuration.GetConnectionString("Default")));

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

為當前項目添加JWT Bearer認證，要求：
- 生成User模型（Username, PasswordHash）
- 添加AuthController的/login端點
- 在Swagger中顯示認證按鈕

public class JwtService
{
    private readonly IConfiguration _config;
    
    public JwtService(IConfiguration config) => _config = config;

    public string GenerateToken(User user)
    {
        var key = new SymmetricSecurityKey(
            Encoding.UTF8.GetBytes(_config["Jwt:Key"]!));
        
        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
        
        var token = new JwtSecurityToken(
            issuer: _config["Jwt:Issuer"],
            audience: _config["Jwt:Audience"],
            claims: new[] { new Claim(ClaimTypes.Name, user.Username) },
            expires: DateTime.Now.AddHours(1),
            signingCredentials: creds);
        
        return new JwtSecurityTokenHandler().WriteToken(token);
    }
}

為Book模型添加數(shù)據(jù)注解驗證：
- Title長度1-100字符
- ISBN必須符合正則表達式^\d{3}-\d{10}$
- Author不能為空

public class Book
{
    public int Id { get; set; }
    
    [Required]
    [StringLength(100, MinimumLength = 1)]
    public string Title { get; set; }
    
    [Required]
    [RegularExpression(@"^\d{3}-\d{10}$", 
        ErrorMessage = "ISBN格式應為XXX-XXXXXXXXXX")]
    public string ISBN { get; set; }
    
    [Required]
    public string Author { get; set; }
}

CS1061: 'AppDbContext' does not contain a definition for 'Books'...

該錯誤表明DbContext缺少DbSet<Book>屬性。解決方案：
1. 在AppDbContext中添加：
   public DbSet<Book> Books { get; set; }
2. 執(zhí)行遷移命令：
   dotnet ef migrations add AddBooksTable
   dotnet ef database update

使用xUnit為BookService編寫測試：
- 測試GetAllBooks返回空列表當數(shù)據(jù)庫為空
- 測試CreateBook返回正確ISBN

public class BookServiceTests : IDisposable
{
    private readonly AppDbContext _context;

    public BookServiceTests()
    {
        var options = new DbContextOptionsBuilder<AppDbContext>()
            .UseSqlite("DataSource=:memory:")
            .Options;
        
        _context = new AppDbContext(options);
        _context.Database.OpenConnection();
        _context.Database.EnsureCreated();
    }

    [Fact]
    public async Task GetAllBooks_ReturnsEmptyList_WhenNoBooks()
    {
        var service = new BookService(_context);
        var result = await service.GetAllBooks();
        Assert.Empty(result);
    }
}

使用Clean Architecture重構當前項目，包含：
- Application層（MediatR + AutoMapper）
- Infrastructure層（EF Core實現(xiàn)）
- API層（Minimal API端點）

// Application/Books/Queries/GetAllBooks.cs
public record GetAllBooksQuery : IRequest<List<BookDto>>;

public class GetAllBooksHandler : IRequestHandler<GetAllBooksQuery, List<BookDto>>
{
    private readonly IApplicationDbContext _context;
    private readonly IMapper _mapper;

    public GetAllBooksHandler(IApplicationDbContext context, IMapper mapper)
    {
        _context = context;
        _mapper = mapper;
    }

    public async Task<List<BookDto>> Handle(GetAllBooksQuery request, CancellationToken ct)
    {
        return _mapper.Map<List<BookDto>>(
            await _context.Books.ToListAsync(ct));
    }
}

優(yōu)化數(shù)據(jù)訪問層：
- 為GetBookById添加AsNoTracking
- 在查詢中使用ProjectTo自動映射DTO
- 添加內(nèi)存緩存策略

public async Task<BookDto> GetBookById(int id)
{
    return await _memoryCache.GetOrCreateAsync($"book_{id}", async entry =>
    {
        entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(5);
        return await _context.Books
            .AsNoTracking()
            .Where(b => b.Id == id)
            .ProjectTo<BookDto>(_mapper.ConfigurationProvider)
            .FirstOrDefaultAsync();
    });
}

dotnet user-secrets init
dotnet user-secrets set "Jwt:Key" "YourSecureKeyHere"

name: .NET Core CI

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
    - name: Setup .NET
      uses: actions/setup-dotnet@v3
      with:
        dotnet-version: 8.0.x
    - name: Restore dependencies
      run: dotnet restore
    - name: Build
      run: dotnet build --configuration Release --no-restore

<PropertyGroup>
  <SonarQubeExclude>**/Migrations/**</SonarQubeExclude>
  <SonarQubeTestProject>false</SonarQubeTestProject>
</PropertyGroup>

@startuml
class Book {
  +int Id
  +string Title
  +string Author
  +string ISBN
}
@enduml

context.Books.Where(b => b.Author == "J.R.R. Tolkien").OrderBy(b => b.Title)

SELECT * FROM Books 
WHERE Author = 'J.R.R. Tolkien' 
ORDER BY Title ASC

<Window>
  <Grid>
    <DataGrid ItemsSource="{Binding Books}">
      <DataGrid.Columns>
        <DataGridTextColumn Header="Title" Binding="{Binding Title}"/>
      </DataGrid.Columns>
    </DataGrid>
  </Grid>
</Window>