.NET Core 2 - Create instance of controller class which has a repository

Question

I have the following controller Class;

public class MyController: Controller
{
    private IValueService _service;

    public MyController(IValueService service)
    {
        this._service = service;
    }

    public void MyMethod()
    {
        var values = _service.GetAll();
    }
}

I would like to create an instance of this Class and call the method MyMethod(), e.g.

var MyCopy = new MyController();
MyCopy.MyMethod();

However i get the message i need to give the required service parameter. How would i create an instance of a controller that has a service (repository) so i can call its methods?

Controller is a normal class, the same as any other class. You must supply a value for service parameter like `var myservice = new ValueService(); var mycopy = new MyController(myservice);` — Al Kepp, Feb 05 '18 at 23:54
No, no, no, you don't ever need to instantiate your own controllers, let the MVC framework do that for you. If you need to call a method, that method should be in it's own, non-controller class, preferably injected with the built in DI container. — DavidG, Feb 05 '18 at 23:58
What dependency does your `IValueService` implementation have that prevents you from calling `service.GetAll()` directly? — Jasen, Feb 06 '18 at 00:05
@DavidG - could you provide an example how to use the DI container with this class / method - could be the answer i am looking for (removing the controller bit) — phicon, Feb 06 '18 at 00:08
This is just normal DI and normal object-oriented programming. Plenty of tutorials online, go look 'em up :) — DavidG, Feb 06 '18 at 00:12
Then instantiate the DbContext. `IValueService service = new ValueService(new DataContext(options))`. Provide options as required by your application. — Jasen, Feb 06 '18 at 00:34
Check out the [dependency injection topic](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/dependency-injection) in the documentation. – *Why* do you want to do this in the first place? Is this for unit testing? — poke, Feb 06 '18 at 00:38
@poke - Well, on startup I would like to run a method in a class that uses a repository. This method first opens a SocketIO connection and then it should use the repository to save new incoming data to the database. New to a lot of concepts, so a bit lost what the correct structure would be. — phicon, Feb 06 '18 at 00:51

score 14 · Answer 1 · answered Mar 28 '18 at 12:54

14

In Startup file add :

 services.AddMvc().AddControllersAsServices();

it will registers all controllers in your application with the DI container.

Then :

   var serviceProvider = HttpContext.RequestServices;
     var controller =(MyController)serviceProvider.GetRequiredService<MyController>();
     controller.Method();

answered Mar 28 '18 at 12:54

Amer Jamaeen

677
8
16

1

this works, but the controller lacks the HttpContext, is there any way we can pass it? – Daniel Sep 24 '21 at 17:52
I have the issue with null HttpContext as well, is there some way to properly initialise this? – Bron Thulke Oct 22 '21 at 02:15

score 9 · Accepted Answer · answered Feb 06 '18 at 01:02

Well, on startup I would like to run a method in a class that uses a repository. This method first opens a SocketIO connection and then it should use the repository to save new incoming data to the database.

Then that logic shouldn’t be inside a controller but in some service type instead which you register with the dependency injection container. Controllers are to respond to requests at certain routes, but your thing sounds like it’s a general initialization step in your application that runs outside of a request. So there should be no controller involved.

Instead, you want to make some service first:

public class MyInitializationService
{
    private readonly IValueService _valueService;

    public MyInitializationService(IValueService valueService)
    {
        _valueService = valueService;
    }

    public void Initialize()
    {
        var values = _valueService.GetAll();
        // do something
    }
}

You then register that class in the ConfigureServices method of your Startup class:

services.AddTransient<MyInitializationService>();

And then, you can inject that type into the Configure method and call its Initialize method:

public void Configure(IApplicationBuilder app, IHostingEnvironment env, MyInitializationService initializationService)
{
    initializationService.Initialize();

    // …
    app.UseStaticFiles();
    app.UseMvc();
}

There are various ways of running something at the beginning when an application starts. Calling it inside Configure is just one way, which may or may not be appropriate depending on how early you want your code to run (since Configure runs very early). Another good way would be to register a callback to the ApplicationStarted event of the application lifetime. I have an answer over here which goes into more details on that.

.NET Core 2 - Create instance of controller class which has a repository

2 Answers2

Linked

Related