.NET中如何使用依赖注入DI

// IRepository.cs
public interface IRepository
{
    void Add(User user);
    User GetById(int id);
}

// UserRepository.cs
public class UserRepository : IRepository
{
    public void Add(User user)
    {
        // 实现添加用户的逻辑
    }

    public User GetById(int id)
    {
        // 实现根据ID获取用户的逻辑
        return new User { Id = id, Name = "John Doe" };
    }
}

// UserService.cs
public class UserService
{
    private readonly IRepository _repository;

    public UserService(IRepository repository)
    {
        _repository = repository;
    }

    public void CreateUser(User user)
    {
        _repository.Add(user);
    }

    public User GetUserById(int id)
    {
        return _repository.GetById(id);
    }
}

// User.cs
public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
}

// Program.cs (对于 .NET 6 或更高版本)
var builder = WebApplication.CreateBuilder(args);

// 配置依赖注入
builder.Services.AddScoped<IRepository, UserRepository>();
builder.Services.AddScoped<UserService>();

var app = builder.Build();

// 配置请求处理管道
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();

app.Run();

// UsersController.cs
[ApiController]
[Route("[controller]")]
public class UsersController : ControllerBase
{
    private readonly UserService _userService;

    public UsersController(UserService userService)
    {
        _userService = userService;
    }

    [HttpPost]
    public IActionResult CreateUser([FromBody] User user)
    {
        _userService.CreateUser(user);
        return Ok();
    }

    [HttpGet("{id}")]
    public IActionResult GetUserById(int id)
    {
        var user = _userService.GetUserById(id);
        return Ok(user);
    }
}