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ASP.NET MVC 4 is a framework for building scalable, standards-based web applicationsusing well-established design patterns and the power of ASP.NET and the .NET Framework.In this article I will give an introduction to ASP.NET MVC 4 from a beginner’s perspective.

This article is meant for all kind of beginner users who wanted to get started with ASP.NET MVC 4. I have included a small comparison between ASP.NET MVC and ASP.NET Web forms for those who have already explored ASP.NET Web forms

Currently ASP>NET MVC 4 is supported in Visual Studio 2010 and Visual Studio 2012, previous versions of Visual Studio does not support ASP.NET MVC 4 as of now. If you don’t have ASP.NET MVC 4 in your box then install MVC 4 for Visual Studio 2010 or else use Visual Studio 2012 to get started with this article, You may refer Setup Environment article for more installation details/procedures.

What is ASP.NET MVC?

ASP.NET supports three different development models named Web Pages, MVC and Web Forms.

ASP.NET MVC is a web application development framework built on top of Microsoft’s .NET Framework. ASP.NET Web Form was a replacement for Microsoft’s Active Server Pages (ASP) but ASP.NET MVC is not a replacement for ASP.NET Web Forms and it’s just an alternate way of making an ASP.NET website.

ASP.NET MVC is open source!- In March 2012, Scott Guthrie announced on his blog that Microsoft had released part of their web stack (including ASP.NET MVC, Razor and Web API) under an open source license (Apache License 2.0).

Download from Codeplex.com

Why MVC?

ASP.NET MVC helps to reduce the complexity of the web application by dividing an application into three layers, Model, View and Controller. This separation (loose coupling) helps in some long term benefits like isolation of components while development and also this separation provides better support for test-driven development (TDD). ASP.NET MVC web site are good in performance and also easy to maintain.

MVC Release History

The Current Version of ASP.NET MVC is 4 and it was released on 15^th Aug 2012. ASP.NET MVC 4 is packaged with Visual Studio 2012 and MVC 4 can be installed for Visual Studio 2010. Below I have mentioned the release history of ASP.NET MVC.

Date	Version
10 Dec 07	ASP.NET MVC CTP
13 Mar 09	ASP.NET MVC 1.0
16 Dec 09	ASP.NET MVC 2 RC
04 Feb 10	ASP.NET MVC 2 RC 2
10 Mar 10	ASP.NET MVC 2
06 Oct 10	ASP.NET MVC 3 Beta
09 Nov 10	ASP.NET MVC 3 RC
10 Dec 10	ASP.NET MVC 3 RC 2
13 Jan 11	ASP.NET MVC 3
20 Sep 11	ASP.NET MVC 4 Developer Preview
15 Feb 12	ASP.NET MVC 4 Beta
31 May 12	ASP.NET MVC 4 RC
15 Aug 12	ASP.NET MVC 4

In this article we are discussing more about the latest version of MVC, that's MVC 4. Read more from Wikipedia on MVC Release History.

MVC Architecture

The Model-View-Controller (MVC) pattern is an architectural design principle that separates the application components of a Web application into three layers. This separation gives you more control over the individual parts of the application, which lets you more easily develop, modify, and test them.

The Model

Model contains and exposes the properties and application logic In a better way we can say that The model represents core business logic and data. In the ePhoneBook Sample the 'PhoneBookModel' class represents the properties of a “Phone Book” in the application and may expose properties such as First Name, Last Name and Mobile Number etc and also it may expose methods.

The View

The View is responsible for creating the response HTML or any responses back to the browser like pdf, html or excel etc. In other way we can sat that the view is responsible for transforming a model or models into a visual representation.

The Controller

Controller is responsible for processing user inputs from view and give responses back to the view. It means that the controller decides the action and performs the tasks/logic based on the parameters.Controller acts as the coordinator between the view and the model.

Comparing ASP.NET MVC with ASP.NET Web Forms

If you have already worked with ASP.NET Web forms then you might be interested to see some comparisons between these two.

The main thing is that both ASP.NET Web form and ASP.NET MVC are built on top of ASP.NET Framework. There are some similarities and differences between these two. ASP.NET Web forms web development is very easy compared to ASP.NET MVC apps. and Web forms doesn't require a developer to be an expert in JavaScript and HTML to write a web application but ASP.NET MVC is full of scripting technologies and it requires a good command over scripting technologies.

ASP.NET Web form is very rich with server controls but in ASP.NET MVC there are no server controls supported and its fully depend on HTML controls. If you look at the below image you can see that no server controls are present in the toolbox.

There is no View State in ASP.NET MVC. we can use HtmlHelpers in ASP.NET MVC for rendering HTML controls in a view. ASP.NET MVC is based on Separation Of Concerns that's why ASP.NET MVC is pluggable and flexible system. Implementing Test projects with ASP.NET MVC is simple than Web forms.

ASP.NET MVC request cycle is very simpler than Web forms and MVC gives a good performance. In my opinion I feel for a Web form developer, ASP.NET MVC is difficult to learn and understand as its much into coding not much drag and drop but once its fully understood then its very easy.

Layout page is the Master page available in ASP.NET MVC and partial views can be considered as a replacement of user control in Web form. Web form uses normal Web-form syntax where as MVC app uses customizable syntax default to Razor.

There are many more similarities and differences, Once you start writing code with ASP.NET MVC you will learn more.

Creating an ASP.NET MVC Application – ePhoneBook

In this article all screen shots are based out of Visual Studio 2012 but If you are using Visual Studio 2010 then you will find similar UIs there too.To Create a new MVC 4 application we need to click on 'New Project' menu. 'New Project' menu can be accessed from the start page itself or File->New->Project menu.

The below given image shows how to create a New Project from start page.

Creating New Project from File->New->Project.

Clicking on New Project menu will show a popup for selecting the required type of Project from the installed templates list. We can create Windows Application or normal ASP.NET Web Application etc using this popup but now we are more interested to create a new ASP.NET MVC 4 Web Application from scratch.

Give a proper name for this new MVC 4 application and click 'OK' button. I have given 'ePhoneBook' name as I'm going to use this project for all my MVC 4 series.

When you click 'OK', you’ll be presented with another dialog with Project Templates

Select appropriate Project Template (discussed in another section), View Engine and also if you want you can opt for creating a Test Project for this application. You can create a test project later also if you don't want to do right now. I have selected the Internet Application with Razor View Engine.

What's a View Engine?

View Engine are responsible for rendering the HTML from your views to the browser. The view engine template will have different syntax for implementation. Currently there are few number of view engines available for MVC and the top four view engines are Razor, traditional ASPX, Spark and NHaml. I have written another article on comparison of different view engines.

Razor is the preferred View Engine for MVC, ASPX View Engine is the legacy View Engine and this option is there for backward compatibility.

I will be explaining more about Razor on another article.

Once you click 'OK' after selecting the appropriate project template Visual Studio will create a MVC Web Application project with default files and folders as per the Template Selection.

If look at the visual studio status bar you can see that the project creation progress and the files adding to the project. ASP.NET MVC 4 project template is using Nuget Package Manager to install and manage the assembly references in your application. the below files in status bar adding by Nuget.

Package.Config File contains the list of the Nuget Package used in this project.

Now Visual Studio created our project in place and the solution file looks like ,

I have explained the Project Items/ Application folder structure in another article, before continuing with our newly created project I just wanted to explain the Project Templates.

Project Templates

Currently MVC 4 Application in Visual Studio 2010 and Visual Studio 2012 offers 6 different types of project templates. (Previously it was 7 but the final version of MVC 4 doesn't shipped with ASP.NET Single Page Application due to some compatibility)

I will be explaining the Basic, Empty, Internet Application, Intranet Application, Mobile Application and Web API project templates here.

Empty

The Empty template created the minimum references and resources required to run an Asp.net MVC application.As you can see in below image, Models, Controllers, App_Data are completely empty folders and View folder only contains web.config and a Global.asax file and web.config.App_Start folder contains 3 configuration files ( FilterConfig.cs, RouteConfige.cs and WebApiConfig.cs ).

This option will be good if you plan to create everything from scratch.

Basic

After comparing the Empty project image and Basic project image we can say that The Basic template is somewhat similar to Empty template. In addition to the Empty project , Content , Script folder are present in this template and Shared folder is present inside Views and also in App_Start folder apart from the three files in empty template, basic template added one more file named BundleConfig.cs (Bundling and minimization).

Same like Empty Template,this option also good if you plan to create everything from scratch.

Internet Application

The Internet Application extends Basic Template with two controllers( Account controller and Home controller) with all the logic and functionality implemented in actions and views. In this template membership management functionality gives the option to user to register and login, change password etc in the website.

It's a template used usually to start a normal web project in action.

Intranet Application

The Intranet Application template is same like the Internet Application template, except that it is preconfigured to use Windows-based authentication.

This template will be a good option if you plan to create an intranet web site.

Mobile Application

The Mobile Application template is another variation of the Internet Application template. This template, however, is optimized for mobile devices and includes the jQuery Mobile JavaScript framework and views that apply the HTML that works best with jQuery Mobile.

If you plan to target touch based mobile devices then this template is the right option.

Web API

The Web API template is yet another variation of the Internet Application template that includes a preconfigured Web API controller.ASP.NET Web API is a framework that makes it easy to build HTTP services that reach a broad range of clients, including browsers and mobile devices. ASP.NET Web API is an ideal platform for building RESTful applications on the .NET Framework.

Web API is a great choice for quickly and easily creating data services that your AJAX-enabled applications can easily consume.

If we want to create a Test project while creating the MVC project itself then we need to mark the Create Unit Test Project Check box. If you don't want to do this at the first time you can add a unit test project later also.

If we are creating MVC Application with Test project then the solution explorer will look like below .

Running our first Application

  Now we will run our newly created ePhoneBook application. We can run this in debug mode or without debug. To run this go to the Menu Debug->Start Debugging/Start without debugging.



  You can also use the shortcut key F5 / Ctrl + F5 to run this application

  The run command is also there in the Standard Toolbar, the below given image shows the run toolbar in VS 2012 IDE.



  The below given image shows the run command in standard toolbar of VS 2010



  Once you have run the application you can see the below Home page



  If you want to debug your application then you need to set a break-point at the location where you want to hit the debugger.

  To set breakpoints just go to the menu Debug->Toggle Breakpoint.



  You can use the shortcut key F9 also for the same. you might want to note the short keys for Step Into (F11) and Step Over (F10). Once you hit the breakpoint you can resume debugging by pressing F5.

  To demonstrate the debugging I have placed two breakpoints, one in Home Controller – About() and About.cshtml. When I clicked on About Menu the first break point got hit.


You can Step Over by F10 or just resume to the next breakpoint by F5. I pressed F5 and the second breakpoint got hit.

If you want see the value then you can see in watch window and also there are other windows too, to add a object to Watch Window, select the required object and right click and click on AddWatch.


  Once you have placed the object in Watch window you can see the current value in that window



  If you resume your breakpoints you can see the About page in action,



  Have you noticed that the url is very user friendly with no extensions and all. The ASP.NET MVC routing takes care of this URL routing. Read more on routing on MSDN.

  To stop debugging you need to press Shift + F5 or go to the Debug menu and click on Stop Debugging.



  Stopping Debugging from the standard toolbar



  If you want to make any changes while debugging then you can edit and continue the application, if that option is enabled. to check this option is enabled or not, go to Tools->Options then


In ASP.MVC, Layout is used to give similar look and feel for the entire application this was called master page in ASP.NET Web forms. Below given the Layout page in our application,

You can see that the Menus like Home, About Contact was shown from this Layout. So how this page is called? So where the content page is placed, it’s simple, the `@RenderBody` mentioned that the content page will be displayed in that area.

  This Layout can be mentioned in individual views or in `_viewstart` file. The ViewStart file called the Layout in below syntax,


While debugging our application we have noticed something named ViewBag. It's a dynamic data dictionary.

As we have used Internet Application Project template the code is generated with Membership management. Let’s have a look into that.

  Now I’m going to create a User named Shemeer using the Register link.

If you want you can place a breakpoint on AccountController’s register action. When I click ‘Register’ Button it reaches the `WebSecurity.CreateUserAndAccount()`.

This method saves my credential to the `aspnet*` database. Wondering J this database was created automatically as part of memebership management and this database by default resides under the `App_Data`folder.

And the connection string has been created inside the web.config also

Now I'm trying to login using the Login page

I’m able to login and my user name is showing in right top corner as logged in

Modifying our first MVC 4 Web Application

Apart from the generated code I’m just going to add some more pieces to this MVC Web Application. I will be publishing a full fledge ePhoneBook on ASP.NET MVC 4 later. This sample code will help you to get more understanding on MVC 4.

The first thing I’m going to do is adding a PhoneBook Model class .

I have changed the PhoneBookModel code as below,

In this class I have mentioned the validation attribute for the elements. The ValidationAttributes are comes fromSystem.ComponentModel.DataAnnotations. There are multiple validation attributes available and all are self-descriptive.

The above image shows the available validation attributes. Read More on Validation Attribute from MSDN.

Now let’s add required views (Create, Edit, Delete, Details, List), to add the views just right click on the View folder and click on Add->Views menu.

Now I’m going to add the Listing view, I have given the View Name as “Index” and selected the 'create a strongly typed view' Model from the Drop-down so that the code will be generated accordingly to the Model. If the created PhoneBookModel is not showing in the dropdown then build the application and then check.

Now we can specify which scaffolding template to use so that the code will be generated as per the template , I have selected “List” template like below

When you click on ‘OK’ button the Index.cshtml is ready.

The same way I have added all files for this sample project

The details page looks like

If you look at the code from Create template all validations are in place

Now we need to add Controller actions for these scaffolding items.

Click on the Add->Controller menu, once you have clicked on that menu then a popup will be shown like below ,

There are multiple controller templates available in this dialogue box

Empty MVC controller

MVC controller with read/write actions and views, using Entity Framework

MVC controller with empty read/write actions

Empty API controller

API controller with read/write actions and views, using Entity Framework

API controller with empty read/write actions

I choosed “MVC controller with empty read/write actions” controller template Now give the controller name as PhoneBookController. Note that MVC requires the name of all controllers to end with "Controller".

Click on “Add” button to add the controller to our application, now the controller file is created as per our template selection and added to our project, click here to see the generated file

Now I’m going to modify the newly added controller file, the first thing I have added a property that will have a default values for the ePhoneBook

After that I have modified the Created method same as below,

If you see this method the return type is ActionResult, What’’s ActionResult. An action result represents a command that the framework will perform on behalf of the action method. The ActionResult class is the base class for action results. It Encapsulates the result of an action method and is used to perform a framework-level operation on behalf of the action method.