[英]Injecting an instance of a service with Autofac
我對Autofac
注入或注冊有問題。 這是我的代碼
資料庫
namespace ClientConfiguration.Data.Repository
{
public class MappingBaseRepository : RepositoryBase<MappingBase>, IMappingBaseRepository
{
public MappingBaseRepository(IDatabaseFactory databaseFactory)
: base(databaseFactory)
{
}
}
public interface IMappingBaseRepository : IRepository<MappingBase>
{
}
}
服務
namespace ClientConfiguration.Service {
public interface IMappingBaseService
{
IEnumerable<MappingBase> GetElements();
void SaveElement();
}
public class MappingBaseService : IMappingBaseService
{
private readonly IMappingBaseRepository MappingBaseRepository;
private readonly IUnitOfWork unitOfWork;
public MappingBaseService(IMappingBaseRepository MappingBaseRepository, IUnitOfWork unitOfWork)
{
this.MappingBaseRepository = MappingBaseRepository;
this.unitOfWork = unitOfWork;
}
#region Members
public IEnumerable<MappingBase> GetElements()
{
var Elements = MappingBaseRepository.GetAll();
return Elements;
}
public void SaveElement()
{
unitOfWork.Commit();
}
#endregion
} }
Autofac初始化
private static void SetAutofacContainer() {
var builder = new ContainerBuilder();
builder.RegisterControllers(Assembly.GetExecutingAssembly());
builder.RegisterType<UnitOfWork>().As<IUnitOfWork>().InstancePerRequest();
builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>().InstancePerRequest();
// Repositories
builder.RegisterAssemblyTypes(typeof(ClientElementRepository).Assembly)
.Where(t => t.Name.EndsWith("Repository"))
.AsImplementedInterfaces().InstancePerRequest();
// Services
builder.RegisterAssemblyTypes(typeof(ClientElementService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.AsImplementedInterfaces().InstancePerRequest();
IContainer container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
}
現在,如果我在控制器內部,則可以毫無問題地獲得服務對象的實例。 但是我必須訪問我的服務IMappingBaseService
才能從此類內的DB獲取數據:
namespace ClientConfiguration.Mappings {
public class CustomDisplayNameAttribute : DisplayNameAttribute {
private static IMappingBaseService mappingBaseService { get; set; }
public CustomDisplayNameAttribute(string value)
: base(GetMessageFromResource(value)) {
}
private static string GetMessageFromResource(string value) {
var els = mappingBaseService.GetElements().ToList();
//get value from DB
//mappingBaseService is always null
return "";
}
}
}
任何幫助將不勝感激! 提前致謝。
代碼演示,例如:
namespace ClientConfiguration.Mappings {
public class CustomDisplayNameAttribute : DisplayNameAttribute {
private static IMappingBaseService _mappingBaseService { get; set; }
public CustomDisplayNameAttribute(string value, IMappingBaseService mappingBaseService)
: base(GetMessageFromResource(value, mappingBaseService)) {
}
private static string GetMessageFromResource(string value, IMappingBaseService mappingBaseService) {
_mappingBaseService = mappingBaseService;
var els = _mappingBaseService .GetElements().ToList();
//OR var els = mappingBaseService.GetElements().ToList();
//get value from DB
//mappingBaseService is always null
return "";
}
}
}
也許您可以修復代碼注冊autofac,因為autofac僅注冊接口,例如:
builder.RegisterAssemblyTypes(typeof(IClientElementRepository).Assembly)
.Where(t => t.Name.EndsWith("Repository"))
.AsImplementedInterfaces().InstancePerRequest();
// Services
builder.RegisterAssemblyTypes(typeof(IClientElementService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.AsImplementedInterfaces().InstancePerRequest();
builder.RegisterAssemblyTypes(typeof(IMappingBaseService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.AsImplementedInterfaces().InstancePerRequest();
解決的辦法是使用屬性注入(實例化autofac init內的類)
我們必須添加這一行
builder.Register(c => new CustomDisplayNameAttribute {
_mappingBaseService = c.Resolve<IMappingBaseService>() });
然后在CustomDisplayNameAttribute中添加空的構造函數
public CustomDisplayNameAttribute() {}
和
public IMappingBaseService _mappingBaseService { get; set; }
為了獲得對象,我們使用
var _mappingBaseService = DependencyResolver.Current.GetService<IMappingBaseService>();
問題是我從DisplayNameAttribute(ASP.NET MVC)附加了CustomDisplayName
public class ClientElementsViewModel {
private static IMappingBaseService _mappingBaseService;
public ClientElementsViewModel(IMappingBaseService mappingBaseService) {
_mappingBaseService = mappingBaseService;
}
[Key]
[Display(Name = "Id")]
public long ClientElementId { get; set; }
[CustomDisplayName("", _mappingBaseService)]
public string CompanyCode { get; set; }
//[CustomDisplayName("")]
public string WebAppBaseUrl { get; set; }
//[CustomDisplayName("")]
public string GuestTraveller { get; set; }
}
我有這個錯誤
錯誤3屬性參數必須是屬性參數類型D:\\ CDS_ADMIN \\ ClientConfiguration.Web \\ ViewModel \\ ClientElementsViewModel.cs的常數表達式,typeof表達式或數組創建表達式22 32 ClientConfiguration.Web
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