.Net Core 依赖注入和类继承

Question

大家好，首先让我感叹一下，我已经搜索了现有的问题，但没有任何结果。

如果我错过了解决这个特定问题的一个，请原谅我。此 .NET Core 3.1 Web API 使用解决方案中的另一个项目 ClassLibrary 来支持其 HTTP 动词方法。 ClassLibrary 中的一个类名为 Cars，它是从 ICars 继承的，可能只是为了 .NET Core 的默认依赖注入目的，但当然这是用于（构造函数注入）Controller CarController。

但是，还有另一个控制器 BlueCarsController 通过其接口 IBlueCars 使用 ClassLibrary BlueCars。请注意，接口公开了在各个类中实现的完全独立的、不同的方法。

我尝试正确注入继承的接口：

   services.AddScoped<IBlueCars, BlueCars>();

导致编译错误：

" 类型 'ModelsClassLibrary.BlueCars' 不能用作类型参数 'TImplementation' 在泛型类型或方法“ServiceCollectionServiceExtensions.AddScoped(IServiceCollection)”中。 没有从 'ModelsClassLibrary.BlueCars' 到 'ModelsClassLibrary.IBlueCars' 的隐式引用转换。 "

这个实现并没有那么重，我无法通过将 BlueCars 的功能组合到 Cars 类中来轻松解决这个问题，但让我们面对现实吧，它们毕竟是真正的“BlueCars”，这是不合适的。

我不欣赏降价，但谢谢

//---------------------class BlueCars--------------------------     
namespace ModelsClassLibrary
{
    public interface IBlueCars
    {
        Task<CallsListDto> GetBlueCarsAsync(string Id, int OtherId, string brand);
    }
    public class BlueCars : Cars
    {
        private readonly ILogger<IBlueCars> _logger;
        private readonly ISomeApiService _someWebApiService;        
        private readonly ICars _cars;        
        private readonly IBlueCars _blueCars;    
        private readonly IConfiguration _configuration;

        public BlueCars(ISomeApiService crmWebApiService,                            
                            ILogger<IBlueCars> logger,
                            ICars cars,
                            IConfiguration configuration,
                            IBlueCars _blueCars
                            )
        {
            _crmWebApiService = crmWebApiService;
            _logger = logger;
            _cars = cars;
            _configuration = configuration;
         
        }


        public async Task<Cars> GetBlueCarsAsync(
                                    string Id, 
                                    int OtherId, 
                                    string brand)        
        {
            var results = new List<Cars>();  
                // blah blah Do Stuff 
        }   
    }
}


//---------------------class Cars--------------------------     
namespace CrmDataAccess
{
    public interface ICars
    {
        Task<CarsListDto> GetCarsAsync(string user, string someBrand);
    }

    public class Cars: ICars
    {
        public const int Nopage = -1;       // Move to crmStringThingie
        private readonly ILogger<CallList> _logger;
        private readonly ICrmWebApiService _crmWebApiService;
        private readonly IConfiguration _configuration;

        public CallList(ICrmWebApiService crmWebApiService, ILogger<CallList> logger, IConfiguration configuration)
        {
            _logger = logger;
            _crmWebApiService = crmWebApiService;
            _configuration = configuration;
        }

        public async Task<Dictionary> GetCarsAsync(string user, string someBrand);
        {
            var result = new CarsListDto();

          // dance fly iterate harvest wash rinse repeat make cool stuff call a service whatever   tada!
          
            return result;  
        }
    }
    
}

//-------------------ConfigureServices

    public void ConfigureServices(IServiceCollection services)
        {           
            //  various config stuff authentication stuff ommitted 
            
              services.AddScoped<ICars, Cars>();   // Works fine for CarsController 
              
              services.AddScoped<IBlueCars, BlueCars>(); // Since BlueCars inherits from Cars how do you do this correctly ? 
                        // the interfaces expose completely different Get methods 
                        
              //---- Various Configure stuff Swagger stuff blah blah 
              
        }
            
            
//-------------------------------

namespace SomeWebApi.Controllers
{
    public class CarsController : BaseController // default logger implementation & other stuff 
    {
    
        private readonly ISomeService _someService;
        private readonly ICars _cars;

        public CallsController(ISomeService _someService,  ICars cars, ILogger<CallsController> logger) : base(_someService, logger)
        {
            _cars = cars;            
        }
        
        
    [HttpGet]
        public async Task<CarsListDto> GetAsync(string user, string someBrand)
        {
                CarsListDto results = await _cars.GetCarsAsync(user,someBrand);
                
                return result;  
            
        }
    }
}

//-------------------------------

namespace SomeWebApi.Controllers
{
    public class BlueCarsController : BaseController // default logger implementation & other stuff 
    {
    
        private readonly ISomeService _someService;
        private readonly IBlueCars _blueCars;

        public BlueCarsController(ISomeService _someService, IBlueCars blueCars, ILogger<CallsController> logger) : base(_someService, logger)
        {
            _blueCars = blueCars;            
        }
        
        
    [HttpGet]
        public async Task<CarsListDto> GetAsync(string id,string brand)
        {
                    // magically get parameters for GetAsync
                    
                CarsListDto results = await _blueCars.GetBlueCarsAsync(Id, OtherId,someBrand);
            
        }
    }
}
        
        
        
        
        
        
        
    

Answer 1

根据显示的代码，错误消息是准确的。 BlueCars 不是从 IBlueCars 派生的

重构BlueCars 派生自IBlueCars 而不是Cars

public class BlueCars : IBlueCars {

    //...

}