c# - 使用我的存储库时无法解析类型的服务

Question

当我尝试访问我的存储库时，我收到一个错误:

InvalidOperationException: Unable to resolve service for type 'software.Notes.Repositories.NoteRepository' while attempting to activate 'software.Notes.Http.Handlers.ShowNote'.

所以，我有一个简单的 SoftwareContext:

public class SoftwareContext : DbContext
{
    public SoftwareContext(DbContextOptions options)
            : base(options)
        { }
        
        public DbSet<Contact> Contact { get; set; }

        public DbSet<Note> Note { get; set; }
    }
}

在我的 startup.cs 文件中实例化:

services.AddDbContext<SoftwareContext>(options =>
    options.UseMySql(
        Configuration.GetConnectionString("DefaultConnection")));

现在，我有一个简单的请求处理程序来显示注释:

[ApiController]
public class ShowNote : Controller
{
    private readonly NoteRepository _note;

    public ShowNote(NoteRepository note)
    {
        _note = note;
    }

    [HttpGet]
    [Route("note/show/{id}")]
    public IActionResult init(int id)
    {
        Note note = _note.Find(id);

        if (note != null) {
            return Ok(note);
        }

        return NotFound();
    }
}

在我的存储库中，我有以下内容:

public abstract class NoteRepository : INoteRepository
{
    private readonly SoftwareContext _context;

    protected NoteRepository(SoftwareContext context)
    {
        _context = context;
    }
    
    public Note Create(Note note)
    {
        var add = _context.Note.Add(note);

        return note;
    }

    public Note Find(int id)
    {
        return _context.Note.FirstOrDefault(x => x.Id.Equals(id));
    }
}

不应该像我目前正在做的那样通过我的存储库的构造函数注入(inject)上下文吗？有人可以解释为什么这不起作用，以及让它起作用的正确方法是什么？

完整的异常日志:

System.InvalidOperationException: Unable to resolve service for type 'software.Notes.Repositories.NoteRepository' while attempting to activate 'software.Notes.Http.Handlers.ShowNote'.at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)at lambda_method(Closure , IServiceProvider , Object[] )at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.b__0(ControllerContext controllerContext)at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.g__CreateController|0(ControllerContext controllerContext)at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Answer 1

您必须将 NoteRepository 添加到 .NET Core 的 IOC 容器中。有三种方法可以做到这一点:在 startup.cs 类中添加

services.AddScoped<INoteRepository, NoteRepository>();

这将为每个请求创建一次 NoteRepository 类的实例

services.AddSingleton <INoteRepository, NoteRepository>();

这意味着您的 NoteRepository 类的实例将在请求之间共享

services.AddTransient <INoteRepository, NoteRepository>();

每次应用程序请求时都会创建实例。

然后你可以通过 Controller 的构造函数注入(inject)依赖

 [ApiController]
 public class ShowNote : Controller
 {
  private readonly INoteRepository _note;
  public ShowNote(INoteRepository note)
    {
        _note = note;
    }
}