我已将依赖项注入与代码优先实体框架集成在一起。但是当我那个时候调用api方法时，我得到了错误。
System.InvalidOperationException：尝试创建类型为'DrugController'的控制器时发生错误。确保控制器具有无参数的公共构造函数。
stackTrace：
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request)
at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()
innerException：
System.ArgumentException：类型'SA_Admin.Controllers.DrugController'没有默认的构造函数
stackTrace：
at System.Linq.Expressions.Expression.New(Type type)
at System.Web.Http.Internal.TypeActivator.Create[TBase](Type instanceType)
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.GetInstanceOrActivator(HttpRequestMessage request, Type controllerType, Func`1& activator)
at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
但是当我删除带有参数的构造函数时，我可以调用而不会出错。
我交叉检查了每个文件，但没有出错。我缺少什么？另外，由于控制器没有构造函数，所以所有帐户方法都可以正常工作。
项目仅是Web api项目。我没有添加mvc。
我使用了Autofac DI nuget程序包。
建议我解决方案。
Startup.cs
public void Configuration(IAppBuilder app)
{
HttpConfiguration config = new HttpConfiguration();
ConfigureOAuth(app);
WebApiConfig.Register(config);
app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
app.UseWebApi(config);
IoCConfig.RegisterDependencies();
}
IOCConfig.cs
public class IoCConfig
{
/// <summary>
/// For more info see
/// :http://docs.autofac.org/en/latest/integration/mvc.html
/// </summary>
public static void RegisterDependencies()
{
#region Create the builder
var builder = new ContainerBuilder();
#endregion
#region Register all authentication dependencies
// REGISTER DEPENDENCIES
builder.RegisterType<SA_AdminEntities>().AsSelf().InstancePerRequest();
#endregion
#region Register all web api controllers for the assembly
builder.RegisterApiControllers(typeof(Startup).Assembly);
#endregion
#region Register modules
builder.RegisterModule(new BusinessLogicInstaller());
builder.RegisterModule(new ReposInstaller());
builder.RegisterModule(new ServicesInstaller());
#endregion
#region Set the dependency resolver to be Autofac
var container = builder.Build();
//for WebApi
GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container);
#endregion
}
}
ServiceInstaller.cs
public class ServicesInstaller : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterAssemblyTypes(typeof(DrugService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.AsImplementedInterfaces()
.InstancePerRequest();
}
}
RepoInstaller.cs
public class ReposInstaller : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<UnitOfWork>().As<IUnitOfWork>().InstancePerRequest();
builder.RegisterType<DbFactory>().As<IDbFactory>().InstancePerRequest();
#region Repositories
builder.RegisterAssemblyTypes(typeof(DrugRepo).Assembly)
.Where(t => t.Name.EndsWith("Repo"))
.AsImplementedInterfaces().InstancePerRequest();
#endregion
}
}
BusinessLogicInstaller.cs
public class BusinessLogicInstaller : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<ParamEncryption>().As<IParamEncryption>().InstancePerRequest();
builder.RegisterType<Mapper>().As<IMapper>().InstancePerRequest();
}
}
WebApiConfig.cs
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
// Web API configuration and services
config.Filters.Add(new ErrorLogApiHandler());
var constraintResolver = new DefaultInlineConstraintResolver
{
ConstraintMap = { ["apiVersion"] = typeof(ApiVersionRouteConstraint) }
};
//removes xml formatter
config.Formatters.Remove(config.Formatters.XmlFormatter);
//enable json formatters
config.Formatters.JsonFormatter.SerializerSettings.ContractResolver =
new CamelCasePropertyNamesContractResolver();
//TODO Turn off move to dev and prod
//enable cors
//config.EnableCors(new EnableCorsAttribute("*", "*", "*"));
//add api versioning
ApiVersion apiVersion = new ApiVersion(1, 0);
config.AddApiVersioning(options =>
{
//will return the headers "api-supported-versions" and "api-deprecated-versions"
options.ReportApiVersions = true;
//TODO define api controllers here with versions
//Like below Example
options.Conventions.Controller<DrugController>().HasApiVersion(apiVersion);
});
//enable attribute routing
config.MapHttpAttributeRoutes(constraintResolver);
}
}
ApiController
[ApiVersion("1.0")]
[RoutePrefix("api/v{version:apiVersion}/Public")]
public class DrugController : ApiController
{
#region Variables
private readonly IDrugService drugService;
private readonly IPersistService persistService;
private readonly IParamEncryption encryptor;
#endregion
#region Constructor
public DrugController(IDrugService drugService, IPersistService persistService, IParamEncryption encryptor)
{
this.drugService = drugService;
this.persistService = persistService;
this.encryptor = encryptor;
}
[Route("Drugs")]
[HttpGet]
public IHttpActionResult Drugs()
{
HttpResponseMessage resp;
try
{
var lstdrugs = drugService.GetDrugs(xx => true);
resp = Request.CreateResponse(HttpStatusCode.OK, lstdrugs);
}
catch (Exception ex)
{
resp = Request.CustomHandleError(ex);
}
return ResponseMessage(resp);
}
#endregion
}
答案 0 :(得分：2)
如果未在autofac容器中注册参数之一，则会遇到相同的错误。实际错误可能是内部异常的多层下降。我只看到注册了IParamEncryption。注册其他两个接口。
答案 1 :(得分：0)