How to setup MVC in ASP.NET Core

How to setup MVC in ASP.NET Core ???

• MVC in ASP.NET Core is an architectural design pattern, implemented by Microsoft.AspNet.Mvc package and composed of three components, which are:
  • Model
  • View
  • Controller

• When a user makes an HTTP request in the browser, this request is received by the Controller, which in turn targets the respective Model.
• After being called by the controller, the model interacts with the database and also implements different operations on the data or request.
• Controllers, not only select the respective Models, but also select the respective Views and pass on the data from Models to Views.
• Here's a graphical representation of How MVC architecture works:

• 

  Now let's setup MVC in ASP.NET Core, so open up your Startup.cs file and in the ConfigureServices Method, we need to add required MVC Services.
• This ConfigureServices Method is a Dependency Injection Container, so if we need to register any dependency in our application, we do it here.
• As you can see in the figure on right side that we have added services.AddMvc() in our Dependency Injection Container.
• Next, we need to add MVC Middleware in our Configure Method, so let's do it

• As you can see in above code that I have added "MVC with Default Route" Middleware in my request processing pipeline.
• When we add this MVC Middleware in our pipeline, by default it makes a search for Home Controller & then finds index Method in it.

Controllers in MVC

• 

  Controllers in MVC architecture are simple C# Classes, inherited from builtin Microsoft.AspNetCore.Mvc.Controller class and are used to handle incoming HTTP requests.
• All public methods / functions in Controllers are normally referred as action methods i.e. we can invoke these methods using a specific URL and can perform required action / task.
• Name of each Controller class is followed bu the word "Controller" i.e. if I want to create a Controller class named Home then it's file name will be HomeController.cs.
• Now let's create a new folder titled Controllers in our Solution Explorer and add a new Class File in it named as HomeControllers.cs, as shown in figure on right side.
• I have used MVC with default route Middleware, which has a default route for homepage and if you check its definition, then you will see that the default Controller is Home and the default action method is index.
• So, now open this HomeController.cs class and add a new index Method in it, as shown in below figure:

• As you can see in above code that I have added a new index Method in HomeController and that's the default home path for MVC Middleware.
• So, now let's run our project and have a look at the browser and if everything goes fine then you will get this line printed on your homepage, instead of index.html file.

Models in MVC

• Models in MVC architecture consists of different classes & interfaces which are requested by the Controllers and then perform different operations on the data objects.
• Models are normally used to interact with the data sources i.e. getting or saving data & then this data is displayed on respective MVC View.
• So,let's create a new folder named Models in our Solution Explorer and also add a new Class file in it named Engineers.cs, as shown in figure on right side.
• As our site is related to Engineering, so I am going to create a new sign up form for engineers, so I have added below code in my Engineers.cs file:

• So, we have created these properties in our Engineers Class and as you can see this Model class contains only our data.
• We haven't added any Method to play with this data, so it's a data class.
• Now we are going to create another class which will have all the Methods i.e. saving this data in database table or search for any data etc.
• But before creating this class, let's first create its Interface in Models folder named IEngineersRepository.
• In this interface, I have declared only one Method rite now but we will add a lot more in coming lectures, so here's it's code:

• As you can see in above figure that have declared a method named GetEngineers(), which will get the Engineers data from database using its Id.
• Now, let's create this second class, which will be implementing this Interface IEngineersRepository.
• So, create a new class in Models folder and give it a name EngineersRepository, code is shown in below figure:

• As you can see in above code that I have inherited this class from Interface IEngineersRepository, that's why it has the implementation of GetEngineers() function.
• Before that Method Implementation, I have just added some hard coded data in the constructor of this class.
• So, every time this class is instantiate, our data will be created, we will replace this data with SQL Database later but for now let's understand the MVC concept.
• So, now we have two classes & one interface in Models folder.