Dependency Injection in .net 4.7? - asp.net-mvc

I'm a little confused as to what integrated options I have for DI. I see it's pretty straightforward for .net core (for my particular projects), but I don't need to build a cross platform app and don't see the advantage to using core. However, it doesn't look like .net framework applications are still setup with Global.asax and without Startup.cs so does that mean there is no integrated DI option for .net framework 4.7? Do I still need to get a 3rd party solution or is there a way to use the same DI workflow in a .net framework project as is used in a core project?

Dependency Injection is not integrated by default in classic asp.net, you need to add a nuget package to handle DI (only integrated by default in asp.net core).

EDIT: Even though I found out how to do it as explained below, I still ended up going with Autofac because I didn't realize the Microsoft's solution only supports constructor injection, but not property injection.
I found instructions on how to do it here. I know link answers are bad, but I don't have time to do any more than this. If someone else wants to make an answer with full instructions I will mark it.
https://scottdorman.blog/2016/03/17/integrating-asp-net-core-dependency-injection-in-mvc-4/
Also note that if you are not using Owin already, it is not required. You can set it up just the same in Application_Start method of Global.asax. Only change you would need to make is when it references the Startup class in a statement that reflectively gets all the Controller classes, you will need to change that to be the class the code is in (or any other class in your assembly).

Related

what is the difference between Autofac , Autofac.MVC ,Autofac.Integration.Mvc dlls

In my MVC web-app I get the following error thrown:
The request lifetime scope cannot be created because the HttpContext
is not available
When I google it I found a solution would be to upgrade my autofac.Mvc dll but I only use autofac dll, Autofac.Integration.Mvc dll etc and I can't find any dll with autofac.MVC
Am I missing any dll?
What is the difference between Autofac , Autofac.MVC ,Autofac.Integration.Mvc dlls?
The documentation on MVC integration may be of help to you going forward, but let me also answer your question.
First, it's good to understand that there's a difference between NuGet packages and DLLs (aka assemblies). Many times the name of the assembly inside a NuGet package is the same as the package, but sometimes the assembly inside has a different name. (And sometimes a NuGet package has more than one assembly.)
So, to answer your question:
NuGet Package Assembly Inside Purpose
------------- --------------------------- -------------------------
Autofac Autofac.dll Core Autofac
Autofac.Mvc5 Autofac.Integration.Mvc.dll ASP.NET MVC 5 integration
So, when you see that you need to update your MVC integration, what it translates to is that you need the latest version of the Autofac.Mvc5 NuGet package.
Autofac.mvc is used when you integrate autofac to your mvc application same as the autofac. WebAPI which is used when you integrate autofac for WebAPI's application.
MVC integration provides dependency injection integration for controllers, model binders, action filters, and views. It also adds per-request lifetime support.
Because the RegisterModelBinders() extension method uses assembly scanning to add the model binders you need to specify what type(s) the model binders (IModelBinder implementations) are to be registered for.
This is done by using the Autofac.Integration.Mvc.ModelBinderTypeAttribute
Likewise there are many other mvc integration supported by this dll, which are listed down in this link
https://autofac.org/apidoc/html/F26C16A.htm
Autofac lets you inject your constructor parameters along with property and method injection
Hence we need all three dlls to make autofac up and functional in mvc application.
Do let me know if you need any further clarification on this.
Thanks!!

how is the NinjectDependencyResolver hooked in?

I have integrated Ninject into an MVC 4 project using the Nuget Ninject.MVC3 package. I can see that App_Start now contains a class called NinjectWebCommon, with a 'bootstrapper'. Following the standard instructions I can inject a concrete instance of an interface into a controller, and the debugger shows me that this is being served up by the NinjectDependencyResolver class.
However: I can't find out, by poking into the Ninject code, where this NinjectDependencyResolver class is being set as the IDependencyResolver using the standard DependencyResolver.SetResolver method. So I'm not sure if I'm just being inept, or whether there's an alternative way this is getting hooked in. Can anyone enlighten me?
IDependencyResolver ships with asp.net MVC framework and allows implementing dependency injection into controllers and other components (asp.net MVC use it internaly) .
I won't explain benefits here but you can read a good introduction here.
When adding an IoC framework (Ninject, Unity, StructureMap, ...) into MVC, you have to plug the Ioc code to the native dependency resolver, with an implementation of IDependencyResolver.
The DependencyResolver static class is the registration point, especially DependencyResolver.SetResolver(IDependencyResolver resolver)
But now, many Ioc framework come with an MVC integration package such as Ninject.MVC our StructureMap.MVC. It's easier for us (and often more robust) and you don't really need to known how it is done.
A quick look at NinjectMvcHttpApplicationPlugin in repositoty Ninject.Web.Mvc will show you the glue.

Decoupling Microsoft.AspNet.Identity.*

I am working in Visual Studio 2013 RC and am testing Forms Authentication using new Microsoft.AspNet.Identity.* packages.
I would to integrate these concepts (Users, Roles, etc, etc) but want to use my own domain models (POCOs) which are in different assembly. I also don't want to create a dependency on Microsoft.AspNet.Identity.* dlls.
Is that even possible?
I found this article which says it is not, but the article is written based on Preview not RC versions of identity packages.
I have updated my sample project which you can find here: Identity RC1 sample
It now implements an entity framework model, it still require a reference to the Microsoft.AspNet.Identity.EntityFramework as I didn't want to reimplement all the Store classes also. But the sample shows how you can use your own POCO classes for the model.
If you want to completely remove the dependency on Microsoft.AspNet.Identity.EntityFramework from your model assembly you need to implement an class implementing the IIdentityStore interface which has properties of the following interfaces:
IUserLoginStore
IRoleStore
IUserSecretStore
ITokenStore
IUserClaimStore
IUserManagementStore
IUserStore
The IIdentityStore class should be in an assembly separate from your model assembly, with a reference to your model assembly. The IIdentityStore assembly would be dependent on ASP.Net Identity core.
Your custom implementation of IIdentityStore would need to somwhow be able to convert to and from your POCO classes to ASP.Net Identity interfaces such as IUser, IUserSecret etc.
Seems to me to be a lot of work for little gain, if you are using EF for your stores anyway.
Taking a dependency on the AspNet.Identity.Core assembly and have some of your POCO classes implementing one tiny interface each, seems a lot simpler to me.
Yes this is a fully supported scenario, basically you will want to use exclude using the Microsoft.AspNet.Identity.EntityFramework dll which has the default EF implementation, but you should be able to reuse the Manager classes and just implement your own custom Stores using your own POCOs which the manager will use just fine via the interface. For RTM its been streamlined and simplified a bit more, I believe the RC version was not quite as streamlined yet.
Updated You can get early access to the RTM bits here: MyGet
Just in case. Maybe I can help someone.
exorcising entity framework from asp.net.Identity
I'd created separate project(class library), then add ref to asp.identity.core,
then I'd implemented my UserStore class there, and feed it my Identity config in Web project.
It works fine in project with complex n-tier architecture.

What is the correct way to share a project across Web and Winforms/console solutions?

I am converting a .NET 2.0 Winforms applications to ASP.NET MVC3. The Winforms solution uses several projects for business logic, and the MVC application includes these projects. The projects are also used by a variety of Windows console applications.
The problem is that these projects use System.Windows.Forms.Application.StartupPath to find files they use, whereas for web development System.Web.HttpRunTime.AppDomainAppPath is used.
I would prefer that both solutions use the same projects and that these projects are modified as little as possible as they are large, old, and relatively undocumented. What is the correct way to address this issue?
Right now I am thinking that I would create a new configuration with each project that would define WEB, and then use #if/#else statements to include the correct depedency and to define the return of the getPath() method.
Before you start plaguing your code with preprocessors, you should consider creating an interface IApplicationConfigurator or IApplicationStarter
public interface IApplicationStarter
{
string GetPath();
}
And inject it with a MvcApplicationStarter or a WinformsApplicationStarter depending on your application. You can then have your project libraries have a dependency on the IApplicationStarter interface. It should require minimal implementation on the projects, and you can reuse the pattern for other common dependencies. Look into dependency injection frameworks as it takes this approach into the next level.
This is what class libraries are for. Create a class library project, move all the common bits there, and then have a separate WinForms and MVC project that both reference your class library.

What's the best design for this problem with IoC and Circular Reference

I'll try to explain in the simple way.
I have a solution (c# 4.0) that contain 4 projects
Framework
DAL
Domain
WebApplication
So my question is:
Framework is the right place to configure my Unity IoC? I want to configure via code and not with xml, so Framework need to know reference of DAL but DAL already knows Framework.
All my projects will know Framework, so where i configure my IoC?
Applications should be configured in the Composition Root, which is as close to the entry point as possible. In your case, that would be the WebApplication. That's the only project which should have a reference to Unity. None of the other projects should have any reference to Unity at all.
In the composition root, you should follow the Register Resolve Release pattern.
See also this answer - it talks about Ninject instead of Unity, but the concept (and hence the answer) is the same.

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