在Unity依赖注入中注入IEnumerable通用接口c＃

Question

我正在使用Web API 2应用程序并使用Unity依赖注入。

我有多种类型的过滤器：名称，品牌，类型...

我想创建一个名为接口：IFilterService并迫使所有其他类来实现它，然后我调用该接口的IEnumerable和注入正确的类型。

界面：

public interface IFilterService<T> 
{ 
    bool CanHandle(FilterType type); 

    Task<ServiceResult<T>> FilterAsync(T entity); 
} 

和类是这样的：

public class NameService : IFilterService<Name> 
{ 
    public bool CanHandle(FacetType type) 
    { 
     return type == FacetType.Name; 
    } 

    public async Task<ServiceResult<Name>> FilterAsync(Name entity) 
    { 
     // Code 
    } 
} 

控制器是这样的：

public class FilterController 
{ 
    private readonly IEnumerable<IFilterService> filters; 

    public MediaController(IEnumerable<IFilterService> filters) 
    { 
     this.filters = filters; 
    } 

    public async Task<HttpResponseMessage> FilterAsync(FilterType type, Name entity) 
    { 
     foreach(var filter in this.filters.Where(x => x.CanHandle(type))) 
     { 
      filter.FilterAsync(entity); 
     } 
     .... 
    } 
} 

一切正常：唯一的问题是在Unity依赖注入中注册接口和类。

container.RegisterType<IEnumerable<IFilterService>, IFilterService[] >(
       new ContainerControlledLifetimeManager()); 
container.RegisterType<IFilterService, NameService>("Name Service", 
       new ContainerControlledLifetimeManager()); 

我收到此错误：

Error CS0305 Using the generic type 'IFilterService' requires 1 type arguments

相同的代码我已经试过了，但与非通用接口和正常工作。

如何解决错误？一些解释可能会非常有用。谢谢。

Answer 1

你有两个选择，第一是注册特定的过滤器类型

container.RegisterType<IEnumerable<IFilterService<Name>>, IFilterService<Name>[] >(
       new ContainerControlledLifetimeManager()); 
container.RegisterType<IFilterService<Name>, NameService>("Name Service", 
       new ContainerControlledLifetimeManager()); 

一样使用

public class FilterController 
{ 
    private readonly IEnumerable<IFilterService<Name>> filters; 

    public MediaController(IEnumerable<IFilterService<Name>> filters) 
    { 
     this.filters = filters; 
    } 

    public async Task<HttpResponseMessage> FilterAsync(FilterType type, Name entity) 
    { 
     foreach(var filter in this.filters.Where(x => x.CanHandle(type))) 
     { 
      filter.FilterAsync(entity); 
     } 
     .... 
    } 
} 

第二个选项是让你的接口不通用的，但你保持功能通用

public interface IFilterService 
{ 
    bool CanHandle(FilterType type); 

    Task<ServiceResult<T>> FilterAsync<T>(T entity); 
} 

public class NameService : IFilterService 
{ 
    public bool CanHandle(FacetType type) 
    { 
     return type == FacetType.Name; 
    } 

    public Task<ServiceResult<T>> FilterAsync<T>(T entity) 
    { 
     if(!entity is Name) 
      throw new NotSupportedException("The parameter 'entity' is not assignable to the type 'Name'"); 

     return FilterAsyncInternal((Name)entity); 
    } 

    private async Task<ServiceResult<Name>> FilterAsyncInternal(Name entity) 
    { 
     //code 
    } 
}