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我在使用Owin的MVC项目中遇到Ninject问题。Ninject请求范围和回调
我对的UnitOfWork的泛型类是不特定于我的项目:
public class UnitOfWork : IUnitOfWork
{
public UnitOfWork(DbContext context)
{...}
}
我用我的自定义的DbContext定义两个库:
public UserRepository : IUserRepository
{
public UserRepository(MyEntities context)
{...}
}
public OrderRepository : IOrderRepository
{
public OrderRepository(MyEntities context)
{...}
}
然后我有使用一个ApiController工作单位和存储库。
public OrderController : ApiController
{
public OrderController(IUnitOfWork uow, IUserRepository userRepository, IOrderRepository orderRepository)
{...}
}
我在一个模块中配置我的Ninject内核。我的绑定具有请求范围。
public class MyModule : Ninject.Modules.NinjectModule
{
public override void Load()
{
// Bind all the repositories
this.Bind(x =>
x.FromAssembliesMatching("*.Repositories")
.SelectAllClasses()
.BindDefaultInterface()
.Configure(c => c.InRequestScope()));
// Bind the DbContext of the application
this.Bind<MyEntities>()
.ToSelf()
.InRequestScope();
// To bind the UnitOfWork, I need to specify the real DbContext to use. For that I use a callback which provide argument to constructor :
this.Bind<IUnitOfWork>()
.To<UnitOfWork>()
.InRequestScope()
.WithConstructorArgument("context", GetContext);
}
private Object GetContext(IContext context, ITarget target)
{
IResolutionRoot resolver;
ActivationBlock scope;
scope = context.Request.GetScope() as ActivationBlock;
resolver = scope ?? (IResolutionRoot)context.Kernel;
var o = resolver.Get<MyEntities>();
var o2 = resolver.Get<MyEntities>();
var same = Object.ReferenceEquals(o, o2);
return o;
}
}
然后我激活Ninject与Owin这样在启动类:
public class Startup
{
public void Configuration(IAppBuilder app)
{
...
app.UseNinjectMiddleware(Startup.CreateKernel);
var config = new HttpConfiguration();
...
app.UseNinjectWebApi(config);
}
private static IKernel CreateKernel()
{
var kernel = new StandardKernel();
kernel.Load(new MyModule());
return kernel;
}
}
这似乎不错,但有一个很大的问题。这些存储库共享相同的DbContext,但UnitOfWork中的DbContext是一个不同的实例。 在函数GetContext中,范围始终为空,因此MyContext实例从内核中检索。布尔变量相同始终为false。问题在这里。内核的Get函数返回一个新实例,而不是请求范围的实例。