ASP.NET MVC Questions & Answers

1. What is MVC?
   MVC stands for Model-View-Controller. It is a software design pattern which was introduced in 1970s. Also, MVC pattern forces a separation of concerns, it means domain model and controller logic are decoupled from user interface (view). As a result maintenance and testing of the application become simpler and easier.
2. Explain MVC design pattern?
   MVC design pattern splits an application into three main aspects: Model, View and Controller.

   1. Model - The Model represents a set of classes that describe the business logic i.e. business model as well as data access operations i.e. data model. It also defines business rules for data means how the data can be changed and manipulated.
   2. View - The View represents the UI components like CSS, jQuery, html etc. It is only responsible for displaying the data that is received from the controller as the result. This also transforms the model(s) into UI.
   3. Controller - The Controller is responsible to process incoming requests. It receives input from users via the View, then process the user's data with the help of Model and passing the results back to the View. Typically, it acts as the coordinator between the View and the Model.

   Today, this pattern is used by many popular framework like as Ruby on Rails, Spring Framework, Apple iOS Development and ASP.NET MVC.
3. What is Domain Driven Design and Development?
   Domain-Driven Design (DDD) is a collection of principles and patterns that help developers to take design decisions to develop elegant systems for different domains. It is not a technology or methodology.

   The main components of DDD are: Entity, Value Object, Aggregate, Service and Repository.

   1. Entity- An object that has an identity- it is unique within the system, like Customer, Employee etc.
   2. Value Object- An object that has no identity within the system like Rate, State etc.
   3. Note- A value object can become an entity depending on the situation.
   4. Aggregate- An aggregate root is a special kind of entity that consumers refer to directly. All consumers of the aggregate root are called as aggregate. The aggregate root guarantees the consistency of changes being made within the aggregate.
   5. Service- A service is a way of dealing with actions, operations and activities within your application.
   6. Repository- A repository is responsible to store and to retrieve your data. It is not a concern how and where data will be persist. So, it can be SQL server, oracle, xml, text file or anything else. Repository is not a Data Access Layer but it refers to a location for storage, often for safety or preservation.

   For more info refer this link http://msdn.microsoft.com/en-us/magazine/dd419654.aspx
4. What is MVP pattern?
   This pattern is similar to MVC pattern in which controller has been replaced by the presenter. This design pattern splits an application into three main aspects: Model, View and Presenter.

   1. Model - The Model represents a set of classes that describes the business logic and data. It also defines business rules for data means how the data can be changed and manipulated.
   2. View - The View represents the UI components like CSS, jQuery, html etc. It is only responsible for displaying the data that is received from the presenter as the result. This also transforms the model(s) into UI.
   3. Presenter - The Presenter is responsible for handling all UI events on behalf of the view. This receive input from users via the View, then process the user's data with the help of Model and passing the results back to the View. Unlike view and controller, view and presenter are completely decoupled from each other’s and communicate to each other’s by an interface.
   Also, presenter does not manage the incoming request traffic as controller.

   This pattern is commonly used with ASP.NET Web Forms applications which require to create automated unit tests for their code-behind pages. This is also used with windows forms.

   Key Points about MVP Pattern

   1. User interacts with the View.
   2. There is one-to-one relationship between View and Presenter means one View is mapped to only one Presenter.
   3. View has a reference to Presenter but View has not reference to Model.
   4. Provides two way communication between View and Presenter.
5. What is MVVM pattern?
   MVVM stands for Model-View-View Model. This pattern supports two-way data binding between view and View model. This enables automatic propagation of changes, within the state of view model to the View. Typically, the view model uses the observer pattern to notify changes in the view model to model.

   1. Model - The Model represents a set of classes that describes the business logic and data. It also defines business rules for data means how the data can be changed and manipulated.
   2. View - The View represents the UI components like CSS, jQuery, html etc. It is only responsible for displaying the data that is received from the controller as the result. This also transforms the model(s) into UI.
   3. View Model - The View Model is responsible for exposing methods, commands, and other properties that helps to maintain the state of the view, manipulate the model as the result of actions on the view, and trigger events in the view itself.

   This pattern is commonly used by the WPF, Silverlight, Caliburn, nRoute etc.

   Key Points about MVVM Pattern

   1. User interacts with the View.
   2. There is many-to-one relationship between View and ViewModel means many View can be mapped to one ViewModel.
   3. View has a reference to ViewModel but View Model has no information about the View.
   4. Supports two-way data binding between View and ViewModel.
6. What is ASP.NET MVC?
   ASP.NET MVC is an open source framework built on the top of Microsoft .NET Framework to develop web application that enables a clean separation of code. ASP.NET MVC framework is the most customizable and extensible platform shipped by Microsoft.
7. What is the advantages of ASP.NET MVC?
   There are following advantages of ASP.NET MVC over Web Forms (ASP.NET):

   1. Separation of concern - MVC design pattern divides the ASP.NET MVC application into three main aspects Model, View and Controller which make it easier to manage the application complexity.
   2. TDD - The MVC framework brings better support to test-driven development.
   3. Extensible and pluggable - MVC framework components were designed to be pluggable and extensible and therefore can be replaced or customized easier then Web Forms.
   4. Full control over application behaviour - MVC framework doesn’t use View State or server based forms like Web Forms. This gives the application developer more control over the behaviors of the application and also reduces the bandwidth of requests to the server.
   5. ASP.NET features are supported - MVC framework is built on top of ASP.NET and therefore can use most of the features that ASP.NET include such as the providers architecture, authentication and authorization scenarios, membership and roles, caching, session and more.
   6. URL routing mechanism - MVC framework supports a powerful URL routing mechanism that helps to build a more comprehensible and searchable URLs in your application. This mechanism helps to the application to be more addressable from the eyes of search engines and clients and can help in search engine optimization.
8. Explain evolution history of ASP.NET MVC?
   Here is the list of released version history of ASP.NET MVC Framework with theirs features.

   ASP.NET MVC1

   1. Released on Mar 13, 2009
   2. Runs on .NET 3.5 and with Visual Studio 2008 & Visual Studio 2008 SP1
   3. MVC Pattern architecture with WebForm Engine
   4. Html Helpers
   5. Ajax helpers
   6. Routing
   7. Unit Testing

   ASP.NET MVC2

   1. Released on Mar 10, 2010
   2. Runs on .NET 3.5, 4.0 and with Visual Studio 2008 & 2010
   3. Strongly typed HTML helpers means lambda expression based Html Helpers
   4. Templated Helpers
   5. UI helpers with automatic scaffolding & customizable templates
   6. Support for DataAnnotations Attributes to apply model validation on both client and server sides
   7. Overriding the HTTP Method Verb including GET, PUT, POST, and DELETE ? Areas for partitioning a large applications into modules
   8. Asynchronous controllers

   ASP.NET MVC3

   1. Released on Jan 13, 2011
   2. Runs on .NET 4.0 and with Visual Studio 2010
   3. The Razor view engine
   4. Enhanced Data Annotations attributes for model validation on both client and server sides
   5. Remote Validation
   6. Compare Attribute
   7. Session less Controller
   8. Child Action Output Caching
   9. Dependency Resolver
   10. Entity Framework Code First support
   11. Partial-page output caching
   12. ViewBag dynamic property for passing data from controller to view
   13. Global Action Filters
   14. Better JavaScript support with unobtrusive JavaScript, jQuery Validation, and JSON binding
   15. Use of NuGet to deliver software and manage dependencies throughout the platform

   ASP.NET MVC4

   1. Released on Aug 15, 2012
   2. Runs on .NET 4.0, 4.5 and with Visual Studio 2010SP1 & Visual Studio 2012
   3. ASP.NET WEB API
   4. Enhancements to default project templates
   5. Mobile project template using jQuery Mobile
   6. Display Modes
   7. Task support for Asynchronous Controllers
   8. Bundling and minification
   9. Support for the Windows Azure SDK

   ASP.NET MVC5

   1. Released on 17 October 2013
   2. Runs on .NET 4.5, 4.5.1 and with Visual Studio 2012 & Visual Studio 2013
   3. One ASP.NET
   4. ASP.NET Identity
   5. ASP.NET Scaffolding
   6. Authentication filters - run prior to authorization filters in the ASP.NET MVC pipeline
   7. Bootstrap in the MVC template
   8. ASP.NET WEB API2
9. What is difference between 3-layer architecture and MVC architecture?
   3-layer architecture separates the application into 3 components which consists of Presentation Layer Business Layer and Data Access Layer. In 3-layer architecture, user interacts with the Presentation layer. 3-layer is a linear architecture.

   MVC architecture separates the application into three components which consists of Model, View and Controller. In MVC architecture, user interacts with the controller with the help of view. MVC is a triangle architecture

   MVC does not replace 3-layer architecture. Typically 3-layer and MVC are used together and MVC acts as the Presentation layer.
10. What is difference between ASP.NET WebForm and ASP.NET MVC?
    Difference between Asp.Net MVC and Web Forms

    Asp.Net Web Forms

    Asp.Net MVC

    Asp.Net Web Form follow a traditional event driven development model.

    Asp.Net MVC is a lightweight and follow MVC (Model, View, Controller) pattern based development model.

    Asp.Net Web Form has server controls.

    Asp.Net MVC has html helpers.

    Asp.Net Web Form supports view state for state management at client side.

    Asp.Net MVC does not support view state.

    Asp.Net Web Form has file-based URLs means file name exist in the URLs must have its physically existence.

    Asp.Net MVC has route-based URLs means URLs are divided into controllers and actions and moreover it is based on controller not on physical file.

    Asp.Net Web Form follows Web Forms Syntax

    Asp.Net MVC follow customizable syntax (Razor as default)

    In Asp.Net Web Form, Web Forms(ASPX) i.e. views are tightly coupled to Code behind(ASPX.CS) i.e. logic.

    In Asp.Net MVC, Views and logic are kept separately.

    Asp.Net Web Form has Master Pages for consistent look and feels.

    Asp.Net MVC has Layouts for consistent look and feels.

    Asp.Net Web Form has User Controls for code re-usability.

    Asp.Net MVC has Partial Views for code re-usability.

    Asp.Net Web Form has built-in data controls and best for rapid development with powerful data access.

    Asp.Net MVC is lightweight, provide full control over markup and support many features that allow fast & agile development. Hence it is best for developing interactive web application with latest web standards.

    Asp.Net Web Form is not Open Source.

    Asp.Net Web MVC is an Open Source.