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针对web api和mvc的同一项目的Unity Dependency注入

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一开始我使用asp.net mvc和unity.mvc为DI启动项目，然后想将web api添加到同一项目并安装unity.webapi但是现在统一依赖注入无法将服务实例注入ApiControllers但是控制器类正在工作 .

UnityConfig.cs

public static class UnityConfig
    {
        private static Lazy<IUnityContainer> container =
          new Lazy<IUnityContainer>(() =>
          {
              var container = new UnityContainer();
              RegisterTypes(container);
              return container;
          });

        public static IUnityContainer Container => container.Value;

        public static void RegisterTypes(IUnityContainer container)
        {
            container.RegisterType<IEmployeeService, EmployeeService>();
            container.RegisterType<IRepository<Employee>, Repository<Employee>>();
        }
    }

ApiController.cs

public class EmployeeApiController : ApiController
    {
        private readonly IEmployeeService _employeeService;

        public EmployeeApiController(IEmployeeService employeeService)
        {
            _employeeService = employeeService;
        }

        public EmployeeApiController(){}



        // GET: api/EmployeeApi
        public IEnumerable<Employee> Get()
        {
            var a = _employeeService.GetAll();
            return a;
        }
}

的Global.asax.cs

public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            GlobalConfiguration.Configure(WebApiConfig.Register);

            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
        }
    }

在apitroller的get动作中，IService通过空指针异常 .

c# asp.net dependency-injection unity-container

2 回答

  • 1

    Web API定义了以下用于解决依赖关系的接口：

    public interface IDependencyResolver : IDependencyScope, IDisposable
{
    IDependencyScope BeginScope();
}

public interface IDependencyScope : IDisposable
{
    object GetService(Type serviceType);
    IEnumerable<object> GetServices(Type serviceType);
}

    正如您在评论中指出的那样，Unity.WebApi nuget包提供了这种实现，您只需在应用程序启动时注册即可 .

    完整参考：

    public static class UnityConfig
{
    public static void RegisterComponents()
    {
        var container = new UnityContainer();
        GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
    }
}

public class WebApiApplication : System.Web.HttpApplication
{
  protected void Application_Start()
  {
    UnityConfig.RegisterComponents();
  }           
}
    回复于
  • -1

    找到解决方案：在UnityConfig.cs上添加以下行：

    public static void RegisterTypes(IUnityContainer container)
{
    //Add this line
     GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);

       container.RegisterType<IEmployeeService, EmployeeService>();
       container.RegisterType<IRepository<Employee>, Repository<Employee>>();
}
    回复于

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