dotnetjunkie
commented
9 years ago When using ASP.NET 5 (vNext), don't try to integrate Simple Injector completely into the ASP.NET pipeline. There is no compelling reason to do so, and it leads to all sorts of complications, because ASP.NET implements the Conforming Container anti-pattern and forces the used DI container into an API that is not compatible with Simple Injector's API.
So instead of trying to replace the default IServiceProvider with Simple Injector, keep them separate and let ASP.NET resolve its own services for its own purpose, and use Simple Injector for where its really good at: resolving the types that belong to your application.
This basically means you just have to do a few tiny things in your Startup class:
- In the
ConfigureServicesmethod, you replace ASP.NET's defaultIControllerActivatorwith a custom version for Simple Injector that intercepts the creation of ASP.NET controllers. In most applications, the creation of controllers is the only thing you need to intercept. - In the
Configuremethod, you configure Simple Injector by registering your own components and your controllers. If your application requires any scoped registrations, you need to apply scoping to ASP.NET's request pipeline as well. If your components depend on any ASP.NET specific abstraction, this is the time to register those as well. This would be as simple as callingcontainer.Register(app.ApplicationServices.GetRequiredService<[AspNetAbstraction]>).
The following is an example of how the startup class would typically look like:
public class Startup
{
private Container container = new SimpleInjector.Container();
public Startup(IHostingEnvironment env) {
// ASP.NET default stuff here
}
// This method gets called by the runtime.
public void ConfigureServices(IServiceCollection services) {
// ASP.NET default stuff here
services.AddInstance<IControllerActivator>(
new SimpleInjectorControllerActivator(this.container));
}
// Configure is called after ConfigureServices is called.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory fac) {
InitializeContainer(app);
RegisterControllers(app);
this.container.Verify();
// Wrap requests in a execution context scope. This allows
// scoped instances to be resolved from the container.
app.Use(async (context, next) => {
using (this.container.BeginExecutionContextScope()) {
await next();
}
});
// ASP.NET default stuff here
}
private void InitializeContainer(IApplicationBuilder app) {
this.container.Options.DefaultScopedLifestyle = new ExecutionContextScopeLifestyle();
// For instance:
container.Register<IUserRepository, SqlUserRepository>(Lifestyle.Scoped);
}
// In the future, this RegisterControllers method will be moved to an integration package.
private void RegisterControllers(IApplicationBuilder app) {
// Register ASP.NET controllers
var provider = app.ApplicationServices.GetRequiredService<IControllerTypeProvider>();
var controllerTypes = provider.ControllerTypes.Select(t => t.AsType());
foreach (Type type in controllerTypes) {
var registration = Lifestyle.Transient.CreateRegistration(type, container);
container.AddRegistration(type, registration);
registration.SuppressDiagnosticWarning(DiagnosticType.DisposableTransientComponent,
"ASP.NET disposes controllers.");
}
}
}
internal sealed class SimpleInjectorControllerActivator : IControllerActivator {
private readonly Container container;
public SimpleInjectorControllerActivator(Container container) { this.container = container; }
[DebuggerStepThrough]
public object Create(ActionContext context, Type type) => this.container.GetInstance(type);
}For more detailed discussion, please see the following articles:
mrchief
davidfowl
I'm trying to hook up Simple Injector in a ASP.NET vNext project. Since, Simple Injector already implements
IServiceProvider, I tried registering it like this:Startup.cs
However, running the app gives me this error:
Not using Simple Injector causes the app to run just fine (although it fails to inject anything but at least it doesn't throw this error).
Not sure what I'm missing.