Ninject | the ninja of .net dependency injectors | Dependency Injection library

The exception is cleared by freezing the image source:

Each time a controller action is called from any web client, that is a request. So when someone visits your site and visits /Pagegroups/Index resolved through routing, that is a request. When you do a Form.Submit from the client, that is a request, make an Ajax call, that is a request.

Do you want the DbContext scoped to be constructed for each request? Absolutely, and no "longer" than a request. For simple applications, using using() within actions is perfectly fine, but it does add a bit of boilerplate code repeating it everywhere. In more complex, long lived applications where you might want to unit test or that could have more complex logic that benefits from breaking down into smaller components shared around, using blocks are a bit of a mess to share the DbContext, so an injected DbContext scoped to the request serves that purpose just fine. Every class instance serving a request is given the exact same DbContext instance.

You don't want a DbContext scoped longer than a request (I.e. Singleton) because while requests from one client may be sequential, requests from multiple users are not. Web servers will respond to various user requests at a time on different threads. EF's DbContext is not thread safe. This catches out new developers where everything seems to work on their machine when testing, only to find that once deployed to a server and handling concurrent requests, errors start popping up.

Also, as DbContext's age, they get bigger and slower tracking more instances of entities. This leads to gradual performance loss, as well as issues as a DbContext serves up cached instances that doesn't reflect data changes from possibly other sources. A new development team might get caught out with the cross-thread issue but introduce locking or such because they want to use EF's caching rather than using a shorter lifespan. (assuming DbContext are "expensive" to create all the time [they're not!:]) This often is the cause of teams calling to abandon EF because it's "slow" without realizing that design decisions prevented them from taking advantage of most of EF's capabilities.

As a general tip I would strongly recommend avoiding the Generic Repository pattern when working with EF. It will give you no benefit other than pigeon-holing your data logic. The power of EF is in the ability to handle the translation of operations against Objects and their relationships down to SQL. It is not merely a wrapper to get down to data. Methods like this:

It seems like you want to get another result. If you are planning to add devices in future (generate buttons dynamically and use custom view) you need to define base interface and implement for each device (sensor, boiler, etc.) which should be made as different module (library). Module should provide some metadata, custom view and something else you want. When you start your app, container loads assemblies with implemented base interface, so you get devices and can generate buttons dynamically using metadata. Then, when necessary, you can use provided view or other provided properties or methods.

You can request IServiceProvider and get the service yourself.

This post has the answer to the question. If IMember member property is made public in MemberController, I can new up the MemberController class and set the value of its member property to the MOCK.

ZonedClock doesn't seem to have any singleton accessor like SystemClock does, so you have to call it's constructor. Using the same approach you used for SystemClock, it would look something like this:

The common solution to this issue is to employ the factory pattern.

You create a factory, that based on some paramter set, during runtime, decide which of the classes to use, and then you merely dependency inject that factory.

There's a few options, here's a couple of them.

1. Use the s parameter to get the service:

The issue is that the hintpath of your project did not point to the right dll path of your packages folder under the solution folder.

If the csproj exists under the proejct folder while the packages folder is on one above folder of the file, then the error happens.

You should change ..\..\ to ..\. Use the right path.

Or try this command under Tools-->Nuget Package Manager-->Package Manager Console