c# - asp.net core 2.0中使用DI注入(inject)BLL服务

Question

我有 asp.net core 2.0 Web Api 项目，它使用 BLL(业务逻辑层)。当我尝试将任何 BLL 服务作为 Dependancy 注入(inject)到我的 Controller 中时出现错误。我已经实现了以下 Controller:

namespace MyProject.WebApi.Controllers
{
    [Route("api/test")]
    public class TestController : Controller
    {
        private readonly ITestService _testService;

        public TestController(ITestService testService)
        {
            _testService = testService;
        }

        [HttpGet, Route("get-all")]
        public List<Test> Get()
        {
            return _testService.GetTestList();
        }
    }
}

我在BLL(单独的项目)中实现了测试服务:

namespace MyProject.Core
{
    public class TestService : ITestService
    {
        private readonly ITestEngine _testEngine;

        public TestService(ITestEngine testEngine)
        {
            _testEngine = testEngine;
        }

        public List<Test> GetTestList()
        {
            return _testEngine.GetTestList();
        }
    }
}

TestService 的界面如下所示:

namespace MyProject.Core
{
    public interface ITestService
    {
        List<Test> GetTestList();
    }
}

build 成功 但是当我调用 TestController 的 Get 方法时出现以下错误:

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[0]
  An unhandled exception has occurred while executing the request
System.InvalidOperationException: Unable to resolve service for type 'MyProject.Infrastructure.Interface.ITestEngine' while attempting to activate 'MyProject.Core.TestService'.

有什么想法吗？

Answer 1

默认情况下，DI 容器不知道您的服务。您需要在 Startup.cs 中的 ConfigureServices 方法中手动注册它们，例如:

public void ConfigureServices(IServiceCollection services)
{
    //Snip
    services.AddScoped<ITestService, TestService>();
}

参见 the docs了解服务所需的生命周期(即作用域、单例或 transient )