MVC project for dependency Injection using ninject.

Introduction

This post is about quick overview of how to do dependency injection using ninject in MVC 4 application.

Background

Many people creating mvc applications just come with out of the box template. But if you move bit advance you have to be aware of how to decouple the components.
Following step by step guideline give you basic idea of how to implement your environment bit clear in separation of concern.

Demonstration

In your application you have service layer implemented (better if you can create separate project for it). Form this layer you can call to database layer.
Keep in mind as default template of mvc application has direct database call in the controller which violate separation of concern and it is not good for large application when it getting bigger.
In service project we have interface like this,

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    public interface IMemberService
    {
         void AddMember();
         void DeleteMember();
         void UpdateMember();
    }

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    public class MemberService:IMemberService
    {
        public void AddMember()
        {
            throw new NotImplementedException();
        }

        public void DeleteMember()
        {
            throw new NotImplementedException();
        }

        public void UpdateMember()
        {
            throw new NotImplementedException();
        }
    }

Now you are going to do dependency injection for controller,
Before that you have to install Ninject and Ninject.Web.Common from the nuget gallary.
now insert following code to override the default constructor creation of your application

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  public class NinjectControllerFactory : DefaultControllerFactory
    {
        private IKernel ninjectKernel;

        public NinjectControllerFactory()
        {
            ninjectKernel = new StandardKernel();
            AddBindings();
        }

        protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
        {
            return controllerType == null? null : (IController)ninjectKernel.Get(controllerType);
        }

        private void AddBindings()
        {
            ninjectKernel.Bind<Service.MemberService.IMemberService>().To<Service.MemberService.MemberService>();
        }
    }

Now you need to apply this changes when application get start class(globle.asax) .insert following line to Application_Start() event.

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ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory());

Now you’re done with dependency injection on your environment.

Interest

I do like to research about new technologies and programming methodologies and application architecture creations.

FluentValidation for server side validation in dependency injection framework by "IValidatorInterceptor"

Today I will try to show you some important hidden feature of FluentValidation.First of all I have to tell you that I am also new to this concept.but as you know FluentValidation is really make you rock star in validation in mvc.simply because it has great seperation of concern (MVC always worry about that .. ;-)).

ok lets start the journy,
so I m try to say little bit domain knoledge about this.(where and when I got this problem and how do I solve it.)

when I join my new project in mvc we came across a following  problem.
This is my controller post action methord.

Ohh...There are lot of server side validations mess up my saving.... :( :(.


can we handle it in separately ? yes why not.

as you see there is a must operator that will help you to do some server side validation.yes.. :D

But My MVC use ninject dependency injection from controller.so I canot do any harm to my framework follows.

so in-order to do server side validation I must use this injected repository(this service mean mostly done serverside repository.)

now If you can undestand what I was fasing U might know What was my problem.ok let me tell you.

from model validator how can I get this injected service ??? :( :(.

after doing some research I fond that public
 class EmployeeModelValidator : AbstractValidator<EmployeeViewModel>, IValidatorInterceptor

has interface called  "IValidatorInterceptor" which has following methords.Which will give you much controll over binding.as you know before the controller being called the validation class will get call by the framework.if you are implementing this interface in your modelvalidator then you have more control over mvc binding.

 public ValidationContext BeforeMvcValidation(System.Web.Mvc.ControllerContext controllerContext, ValidationContext validationContext)
     
and

  public FluentValidation.Results.ValidationResult AfterMvcValidation(System.Web.Mvc.ControllerContext controllerContext, ValidationContext validationContext, FluentValidation.Results.ValidationResult result)

oh now prolem is over ??no.still I cant get the controller variables.as define in the controller.

   
but microsoft introduce dynamic key world in 2010.so by using that you can get pass the repository service.

now you can do what ever server side valdation that you need.injected from controller.

NB:

• This is one usage of IValidatorInterceptor,but there are much more other.prime purpose of using this interface is to do some validation before and binding the model validation.
• You have only one model validator for all your model validation in controller so be careful if you do editing also.
• you can do further enhance to pass model parameter as follows, 

private bool IsNICAlreadyExist(EmployeeViewModel v, string NIC)
          which pass model to the your validation function.so your rule is like this,


  RuleFor(x => x.NIC).Matches(@"[0-9]{9}[vVxX]").WithMessage("Enter valid NIC number ").Must(IsNICAlreadyExist).WithMessage("NIC already exists in the application");

this is one methord of doing that if you have other methords please commet me. thank you.
here for this I do thanks to my teq lead askar mustafa.