Question

我是ASP .net核心的新手。它给了我一个依赖项注入错误，如下所示：

InvalidOperationException：尝试激活“ SpinIt.Web.Controllers.CartController”时，无法解析类型为“ Spinit.Data.Services.Repository.GameRepository”的服务。 Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService（IServiceProvider sp，Type type，Type requiredBy，bool isDefaultParameterRequired）

StackTrace如下：

Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, bool isDefaultParameterRequired)
lambda_method(Closure , IServiceProvider , object[] )
Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider+<>c__DisplayClass4_0.<CreateActivator>b__0(ControllerContext controllerContext)
Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider+<>c__DisplayClass5_0.<CreateControllerFactory>g__CreateController|0(ControllerContext controllerContext)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.MigrationsEndPointMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.DatabaseErrorPageMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

CartController 代码

public class CartController:Controller
{
    private readonly GameRepository _gameRepository;
    private readonly Cart _cartRepository;

    public CartController(GameRepository gameRepository, Cart cartRepository)
    {
        _gameRepository = gameRepository;
        _cartRepository = cartRepository;
    }

    public ViewResult Index()
    {
        var items = _cartRepository.GetCartItems();
        _cartRepository.CartItems = items;

        var sCVM = new CartViewModel
        {
            Cart = _cartRepository,
            CartTotal = _cartRepository.GetCartTotal()
        };
        return View(sCVM);
    }
}

我还向 Startup.cs

添加了服务

services.AddScoped<IGame, GameRepository>();
services.AddScoped<ICartItem, CartItemRepository>();

Answer 1

您已在Startup.cs文件中使用.NET Core服务容器将IGame注册为服务类型，并将GameRepository注册为实现类型。因此，显然IGame已注册在服务容器中，并且只能通过DI注入IGame类型。 DI系统不知道名为GameRepository的服务，因为它未在DI服务容器中注册。

请在控制器构造函数中进行如下更改：

private readonly IGame _gameRepository;
private readonly ICartItem _cartRepository;

public CartController(IGame gameRepository, ICartItem cartRepository)
{
    _gameRepository = gameRepository;
    _cartRepository = cartRepository;
}

Answer 2

您正在使用实现作为构造函数参数，您没有在服务中提及它。尝试使用该界面。

public class CartController:Controller
{
    private readonly IGame _gameRepository;
    private readonly ICartItem _cartRepository;

    public CartController(IGame gameRepository, ICartItem cartRepository)
    {
        _gameRepository = gameRepository;
        _cartRepository = cartRepository;
    }

    public ViewResult Index()
    {
        var items = _cartRepository.GetCartItems();
        _cartRepository.CartItems = items;

        var sCVM = new CartViewModel
        {
            Cart = _cartRepository,
            CartTotal = _cartRepository.GetCartTotal()
        };
        return View(sCVM);
    }
}

处理请求时发生未处理的异常-ASP .NET Core

2 个答案: