Unable to Create DbContext per Request with Simple Injector

Question

Simple Inject is throwing the following exception when attempting to register my DbContext. The supplied connection string is not valid, because it contains insufficient mapping or metadata information. Parameter name: connectionString I'm new to DI and could be missing something fairly obvious. The connection string looks fine. It is the same one that gets used to create the DbContext normally. I was attempting the solution here ``` public static class SimpleInjectorInitializer { ///

Initialize the container and register // it as MVC3 Dependency Resolver.

public static void Initialize() { var container = new Container(); InitializeContainer(container); container.RegisterMvcControllers( Assembly.GetExecutingAssembly()); container.RegisterMvcAttributeFilterProvider(); container.Verify(); DependencyResolver.SetResolver( new SimpleInjectorDependencyResolver(container)); } private static void InitializeContainer( Container container) { } } ``` Update: I still haven't so…

Accepted Answer

The root cause is burried deep down in the inner exceptions. When inspecting the stack trace, you will be able to find the cause of this. The reason is in the following two inner exceptions:

InvalidOperationException: Unable to determine application context. The ASP.NET application path could not be resolved.

and:

InvalidOperationException: This method cannot be called during the application's pre-start initialization stage.

In other words, this exception is caused by a timing problem. I'm not sure if you can change your connection string to solve this, but you can also move your initalization to a later moment in starting the application. You can do this as follows:

- Remove the `[assembly: WebActivator.PreApplicationStartMethod]` (top line) of the SimpleInjectorInitializer.cs class.

- Add a call to the `SimpleInjectorInitializer.Initialize()` method in the `Application_Start()` event of the global asax.

After doing this, initializing (and especially, verifying) of the object graph is done after the pre-init state, which seems to be too early for EF in an ASP.NET environment.

Another option is to remove the `container.Verify();` call from the `SimpleInjectorInitializer.Initialize` method, since it is the early verification process that is killing you. However, please read this Verify the container’s configuration first, to see alternatives, before doing so.

Unable to Create DbContext per Request with Simple Injector

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