C#•3y ago

dependency injection net framework

hi all, I'm following a reference on how to use dependency injection in net framework https://stackoverflow.com/questions/43311099/how-to-create-dependency-injection-for-asp-net-mvc-5 i tried to implement the solution the way they register the services, but when i run the controller i saw that the Interface is not initialized.. even though when i try to debug, the program run through the initialization part like this

services.AddScoped<IDailyConversion, DailyConversion>();

services.AddScoped<IDailyConversion, DailyConversion>();

... does anyone have any idea maybe what could be the issue..?

Stack Overflow

How to create dependency injection for ASP.NET MVC 5?

Creating Dependency Injection with ASP.NET Core is fairly easy. The documentation explains it very well here and this guy has a killer video to explain it. However, I want to do the same thing wit...

29 Replies

Unknown User•3y ago

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Yawnder•3y ago

IDaily != IDailyConversion It doesn't matter if IDaily inherit from IDailyConversion or not, the registration has to be exact.

jin.fuyouOP•3y ago

my bad, i mistype the name, yup.. it should be (edited the message)

services.AddScoped<IDailyConversion, DailyConversion>();

services.AddScoped<IDailyConversion, DailyConversion>();

Unknown User•3y ago

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jin.fuyouOP•3y ago

yes.. actually i implemented the interface.. tbh.. i tested the code works in net core, but for some reason i have to do it in net framework, so i try to move the code, register all the service and all in net framework way... but somehow i got null value...

Unknown User•3y ago

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jin.fuyouOP•3y ago

im using net framework 4.8 version.. will net version affect the dependency injection implementation (like it can't be used in a certain version..)? @Yawnder @MansEternalQuest can i understand.. is it not possible to pass Interface to a controller constructor (in net framework) like above..?

Yawnder•3y ago

Not too sure why you would say that, but no. @qian Can you show your registrations? All of them.

jin.fuyouOP•3y ago

yup.. it's a bit long so i do screenshots instead of copying the code.. here are the services that are registered.. actually because only after i added an empty constructor for this DailyConversion controller it will works, but not the constructor with interface parameter inside.. so i wondering if it's different in net framework..

Yawnder•3y ago

If you put a breakpoint in your AddControllersAsServices, does it hit it properly? What does your Controller look like? (the class definition and the constructor)

jin.fuyouOP•3y ago

yes.. it does..

Yawnder•3y ago

You do AddScope<DailyConversion>(). If you're trying to inject an interface, this will not work.

jin.fuyouOP•3y ago

my controller looks like this..

Yawnder•3y ago

No, I mean inside AddControllersAsServices. Do you see it hit the controller registration. Ok. Remove that parameterless constructor Change AddScope<DailyConversion>() for AddScope<IDailyConversion, DailyConversion>() like it was before.

jin.fuyouOP•3y ago

yup.. it enter the class as well..

Yawnder•3y ago

Inside the foreach. Can you see type == typeof(DailyController) ? (The answer is probably no)

jin.fuyouOP•3y ago

no.. it doesnt enter inside the for loop...

Yawnder•3y ago

So it means your lambda filters it out. Can you just add IController on your controller and try again? (Maybe it's not registering it as implementing IController because Controller inherits from it, and not directly.) DailyController : Controller, IController But that wouldn't change anything actually. Can you explicitly register your controller and try again?

jin.fuyouOP•3y ago

the program still doesnt enter this loop

Yawnder•3y ago

No. services.AddScoped<DailyController>(); It's normal that it doesn't enter the loop.

jin.fuyouOP•3y ago

still the same message from the browser with parameterless constructor..

Yawnder•3y ago

I really feel like your whole project is setup wrong, but it's hard to say with bits and pieces.

jin.fuyouOP•3y ago

im not sure if this part could be an issue..

            services.AddControllersAsServices(typeof(StartUp).Assembly.GetExportedTypes()
            .Where(t => !t.IsAbstract && !t.IsGenericTypeDefinition)
            .Where(t => typeof(IController).IsAssignableFrom(t)
            || t.Name.EndsWith("Controller", StringComparison.OrdinalIgnoreCase)));

            services.AddControllersAsServices(typeof(StartUp).Assembly.GetExportedTypes()
            .Where(t => !t.IsAbstract && !t.IsGenericTypeDefinition)
            .Where(t => typeof(IController).IsAssignableFrom(t)
            || t.Name.EndsWith("Controller", StringComparison.OrdinalIgnoreCase)));

because this part im following the link from stackoverflow.. but then i found another version of answer from stackoverflow that we dont use "StartUp".. https://stackoverflow.com/questions/54584671/dependency-injection-in-net-4-7

jin.fuyouOP•3y ago

i think im able to setup a new project.. is it the issue with web application project that i setup?

jin.fuyouOP•3y ago

Yawnder•3y ago

No idea what the issue is. You have all the information, and all I have are bits and pieces through screenshots.

jin.fuyouOP•3y ago

is it possible if i push the project to github for you to see clearer.. is that okay?

Yawnder•3y ago

Nah, I already spent enough time on that, I need to go to bed, sorry.

jin.fuyouOP•3y ago

Okay 😢

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dependency injection net framework