MVC Question and Answer Part 2

What are the 3 main components of an ASP.NET MVC application?
1. M - Model
2. V - View
3. C - Controller

In which assembly is the MVC framework defined?
System.Web.Mvc

Is it possible to combine ASP.NET webforms and ASP.MVC and develop a single web application?
Yes, it is possible to combine ASP.NET webforms and ASP.MVC and develop a single web application.

What does Model, View and Controller represent in an MVC application?
Model: Model represents the application data domain. In short the applications business logic is contained with in the model.

View: Views represent the user interface, with which the end users interact. In short the all the user interface logic is contained with in the UI.

Controller: Controller is the component that responds to user actions. Based on the user actions, the respective controller, work with the model, and selects a view to render that displays the user interface. The user input logic is contained with in the controller.

What is the greatest advantage of using asp.net mvc over asp.net webforms?
It is difficult to unit test UI with webforms, where views in mvc can be very easily unit tested.

Which approach provides better support for test driven development - ASP.NET MVC or ASP.NET Webforms?
ASP.NET MVC

What are the advantages of ASP.NET MVC?
1. Extensive support for TDD. With asp.net MVC, views can also be very easily unit tested.
2. Complex applications can be easily managed
3. Seperation of concerns. Different aspects of the application can be divided into Model, View and Controller.
4. ASP.NET MVC views are light weight, as they donot use viewstate.

Is it possible to unit test an MVC application without running the controllers in an ASP.NET process?
Yes, all the features in an asp.net MVC application are interface based and hence mocking is much easier. So, we don't have to run the controllers in an ASP.NET process for unit testing.

Is it possible to share a view across multiple controllers?
Yes, put the view into the shared folder. This will automatically make the view available across multiple controllers.

What is the role of a controller in an MVC application?
The controller responds to user interactions, with the application, by selecting the action method to execute and alse selecting the view to render.

Where are the routing rules defined in an asp.net MVC application?
In Application_Start event in Global.asax

Name a few different return types of a controller action method?
The following are just a few return types of a controller action method. In general an action method can return an instance of a any class that derives from ActionResult class.
1. ViewResult
2. JavaScriptResult
3. RedirectResult
4. ContentResult
5. JsonResult

What is the significance of NonActionAttribute?
In general, all public methods of a controller class are treated as action methods. If you want prevent this default behaviour, just decorate the public method with NonActionAttribute.

What is the significance of ASP.NET routing?
ASP.NET MVC uses ASP.NET routing, to map incoming browser requests to controller action methods. ASP.NET Routing makes use of route table. Route table is created when your web application first starts. The route table is present in the Global.asax file.

What are the 3 segments of the default route, that is present in an ASP.NET MVC application?
1st Segment - Controller Name
2nd Segment - Action Method Name
3rd Segment - Parameter that is passed to the action method

Example: http://venkatrangala.com/Employee/Details/5
Controller Name = Customer
Action Method Name = Details
Parameter Id = 5

ASP.NET MVC application, makes use of settings at 2 places for routing to work correctly. What are these 2 places?
1. Web.Config File : ASP.NET routing has to be enabled here.
2. Global.asax File : The Route table is created in the application Start event handler, of the Global.asax file.

What is the adavantage of using ASP.NET routing?
In an ASP.NET web application that does not make use of routing, an incoming browser request should map to a physical file. If the file does not exist, we get page not found error.

An ASP.NET web application that does make use of routing, makes use of URLs that do not have to map to specific files in a Web site. Because the URL does not have to map to a file, you can use URLs that are descriptive of the user's action and therefore are more easily understood by users.

What are the 3 things that are needed to specify a route?
1. URL Pattern - You can include placeholders in a URL pattern so that variable data can be passed to the request handler without requiring a query string.
2. Handler - The handler can be a physical file such as an .aspx file or a controller class.
3. Name for the Route - Name is optional.

Is the following route definition a valid route definition?
{controller}{action}/{id}
No, the above definition is not a valid route definition, because there is no literal value or delimiter between the placeholders. Therefore, routing cannot determine where to separate the value for the controller placeholder from the value for the action placeholder.

What is the use of the following default route?
{resource}.axd/{*pathInfo}
This route definition, prevent requests for the Web resource files such as WebResource.axd or ScriptResource.axd from being passed to a controller.

What is the difference between adding routes, to a webforms application and to an mvc application?
To add routes to a webforms application, we use MapPageRoute() method of the RouteCollection class, where as to add routes to an MVC application we use MapRoute() method.

How do you handle variable number of segments in a route definition?
Use a route with a catch-all parameter. An example is shown below. * is referred to as catch-all parameter.
controller/{action}/{*parametervalues}

What are the 2 ways of adding constraints to a route?
1. Use regular expressions
2. Use an object that implements IRouteConstraint interface

Give 2 examples for scenarios when routing is not applied?
1. A Physical File is Found that Matches the URL Pattern - This default behaviour can be overriden by setting the RouteExistingFiles property of the RouteCollection object to true.
2. Routing Is Explicitly Disabled for a URL Pattern - Use the RouteCollection.Ignore() method to prevent routing from handling certain requests.

What is the use of action filters in an MVC application?
Action Filters allow us to add pre-action and post-action behavior to controller action methods.

If I have multiple filters impleted, what is the order in which these filters get executed?
1. Authorization filters
2. Action filters
3. Response filters
4. Exception filters

What are the different types of filters, in an asp.net mvc application?
1. Authorization filters
2. Action filters
3. Result filters
4. Exception filters

Give an example for Authorization filters in an asp.net mvc application?
1. RequireHttpsAttribute
2. AuthorizeAttribute

Which filter executes first in an asp.net mvc application?
Authorization filter


What are the levels at which filters can be applied in an asp.net mvc application?
1. Action Method
2. Controller
3. Application
[b]Is it possible to create a custom filter?[/b]
Yes

What filters are executed in the end?
Exception Filters

Is it possible to cancel filter execution?
Yes

What type of filter does OutputCacheAttribute class represents?
Result Filter

What are the 2 popular asp.net mvc view engines?
1. Razor
2. .aspx

What symbol would you use to denote, the start of a code block in razor views?
@

What symbol would you use to denote, the start of a code block in aspx views?
<%= %>

In razor syntax, what is the escape sequence character for @ symbol?
The escape sequence character for @ symbol, is another @ symbol

When using razor views, do you have to take any special steps to proctect your asp.net mvc application from cross site scripting (XSS) attacks?
No, by default content emitted using a @ block is automatically HTML encoded to protect from cross site scripting (XSS) attacks.

When using aspx view engine, to have a consistent look and feel, across all pages of the application, we can make use of asp.net master pages. What is asp.net master pages equivalent, when using razor views?
To have a consistent look and feel when using razor views, we can make use of layout pages. Layout pages, reside in the shared folder, and are named as _Layout.cshtml

What are sections?
Layout pages, can define sections, which can then be overriden by specific views making use of the layout. Defining and overriding sections is optional.

What are the file extensions for razor views?
1. .cshtml - If the programming lanugaue is C#
2. .vbhtml - If the programming lanugaue is VB

How do you specify comments using razor syntax?
Razor syntax makes use of @* to indicate the begining of a comment and *@ to indicate the end. An example is shown below.
@* This is a Comment *@

MVC Question And Answer Part1

What are the 3 main components of an ASP.NET MVC application?
1. M - Model
2. V - View
3. C - Controller

In which assembly is the MVC framework defined?
System.Web.Mvc

Is it possible to combine ASP.NET webforms and ASP.MVC and develop a single web application?
Yes, it is possible to combine ASP.NET webforms and ASP.MVC and develop a single web application.

What does Model, View and Controller represent in an MVC application?
Model: Model represents the application data domain. In short the applications business logic is contained with in the model.

View: Views represent the user interface, with which the end users interact. In short the all the user interface logic is contained with in the UI.

Controller: Controller is the component that responds to user actions. Based on the user actions, the respective controller, work with the model, and selects a view to render that displays the user interface. The user input logic is contained with in the controller.

What is the greatest advantage of using asp.net mvc over asp.net webforms?
It is difficult to unit test UI with webforms, where views in mvc can be very easily unit tested.

Which approach provides better support for test driven development - ASP.NET MVC or ASP.NET Webforms?
ASP.NET MVC

What are the advantages of ASP.NET MVC?
1. Extensive support for TDD. With asp.net MVC, views can also be very easily unit tested.
2. Complex applications can be easily managed
3. Seperation of concerns. Different aspects of the application can be divided into Model, View and Controller.
4. ASP.NET MVC views are light weight, as they donot use viewstate.

Is it possible to unit test an MVC application without running the controllers in an ASP.NET process?
Yes, all the features in an asp.net MVC application are interface based and hence mocking is much easier. So, we don't have to run the controllers in an ASP.NET process for unit testing.

Is it possible to share a view across multiple controllers?
Yes, put the view into the shared folder. This will automatically make the view available across multiple controllers.

What is the role of a controller in an MVC application?
The controller responds to user interactions, with the application, by selecting the action method to execute and alse selecting the view to render.

Where are the routing rules defined in an asp.net MVC application?
In Application_Start event in Global.asax

Name a few different return types of a controller action method?
The following are just a few return types of a controller action method. In general an action method can return an instance of a any class that derives from ActionResult class.
1. ViewResult
2. JavaScriptResult
3. RedirectResult
4. ContentResult
5. JsonResult

What is the significance of NonActionAttribute?
In general, all public methods of a controller class are treated as action methods. If you want prevent this default behaviour, just decorate the public method with NonActionAttribute

How MVC application works

Introduction

This article is intended to provide basic concepts and fundamentals of ASP.NET MVC (Model View Controller) architecture workflow for beginners.

“M” “V” “C” stands for “MODEL” “VIEW” “CONTROLLER”. ASP.NET MVC is an architecture to develop ASP.NET web applications in a different manner than the traditional ASP.NET web development. Web applications developed with ASP.NET MVC are even more SEO (Search Engine) friendly.

Developing ASP.NET MVC application requires Microsoft .NET Framework 3.5 or higher.

MVC Interaction with Browser

Like a normal web server interaction, MVC application also accepts requests and responds to the web browser in the same way.

Inside MVC Architecture

The entire ASP.NET MVC architecture is based on Microsoft .NET Framework 3.5 and in addition uses LINQ to SQL Server.

What is a Model?

1.     MVC model is basically a C# or VB.NET class

2.    A model is accessible by both controller and view

3.    A model can be used to pass data from Controller to view

4.    A view can use model to display data in page.

What is a View?

1.     View is an ASPX page without having a code behind file

2.    All page specific HTML generation and formatting can be done inside view

3.    One can use Inline code (server tags ) to develop dynamic pages

4.    A request to view (ASPX page) can be made only from a controller’s action method

What is a Controller?

1.     Controller is basically a C# or VB.NET class which inherits system.mvc.controller

2.    Controller is a heart of the entire MVC architecture

3.    Inside Controller’s class action methods can be implemented which are responsible for responding to browser OR calling views.

4.    Controller can access and use model class to pass data to views

5.    Controller uses ViewData to pass any data to view

MVC File Structure & File Naming Standards

MVC uses a standard directory structure and file naming standards which are a very important part of MVC application development.

Inside the ROOT directory of the application, there must be 3 directories each for model, view and Controller.

Apart from 3 directories, there must have a Global.asax file in root folder, and a web.config like a traditional ASP.NET application.

·         Root [directory]

o    Controller [directory]

§  Controller CS files

o    Models [directory]

§  Model CS files

o    Views [directory]

§  View aspx/ascx files

o    Global.asax

o    Web.config

ASP.NET MVC Execution Life Cycle

Here is how MVC architecture executes the requests to browser and objects interactions with each other.

A step by step process is explained below [Refer to the figure as given below]:

Browser Request (Step 1)

Browser request happens with a specific URL. Let’s assume that the user enters URL like: [xyz.com]/home/index/

Job of Global.asax – MVC routing (Step 2)

The specified URL will first get parsed via application_start() method inside Global.asax file. From the requested URL, it will parse the Controller, Action and ID.

So for [xyz.com]/home/index/:

·         Controller = home

·         Action = index()

·         ID = empty — we have not specified ID in [xyz.com]/home/index/, so it will consider as empty string

Controller and Action methods (Step 3)

MVC now finds the home controller class in controller directory. A controller class contains different action methods,

There can be more than one action method, but MVC will only invoke the action method which has been parsed from the URL, its index() in our case.

So something like: homeController.index() will happen inside MVC controller class.

Invoking action method can return plain text string OR rendered HTML by using view.

Call to View (Step 4)

Invoking view will return view(). A call to view will access the particular ASPX page inside the view directory and generate the rendered HTML from the ASPX and will respond back to the browser.

In our case, controller was home and action was index(). So calling view() will return a rendered HTML from the ASPX page located at /views/home/index.aspx.

Hosting MVC Application In IIS

Introduction

This article explains how to host your MVC 5 App in IIS Express and store the data and information in the database created in SQL Server. Visual Studio uses the ASP.NET Development Server as a default and here I am using IIS Server to host a MVC 5 App. As you know, in Visual Studio 2013 Preview the ASP.NET Web Application uses a MVC5 project template and MVC5 uses the Bootstrap theme to display the application, so here I am using the Visual Studio 2013 Preview to develop an application using the MVC project template.

Prerequisites

The following are the prerequisites to develop a MVC 5 application:

• Visual Studio 2013 Preview
• SQL Server 2008 or 2012

Creating MVC 5 Application

Let's start to develop an application in MVC 5 using the following procedure.

Step 1: Open Visual Studio 2013 Preview

Step 2: Click on "New Project" and enter the application name.

Step 3: Select MVC project template to create the project.

Step 4: In your Solution Explorer, open the Web.Config file.

As you can see, the connection property is available on my file:

<add name="DefaultConnection"

     connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\aspnet-MvcIISDemo-20130911053147.mdf;Initial Catalog=aspnet-MvcIISDemo-20130911053147;Integrated Security=True"

     providerName="System.Data.SqlClient" />

Now, change the code above as shown below:

Step 5: Debug your application and click on the "Register Link" as shown below:

You will see your UserName in your next page window:

Verify in SQL Server 2012

As you can see, I did not create a database nor any table in my SQL Server 2012. When I declared my connection string, it automatically created a database and table in my SQL Server. You do not need to worry about that.

Let's see my database in my SQL Server Object Explorer.

 Select your database and open the Users Table. You can see the user information as shown below:

Publish Application

The next step is to host in IIS 8 (IIS Express). For that use the following procedure:

Step 1: In your Solution Explorer select your project and right-click to select Publish.

Step 2: Select NewProfile and click Next as shown below:

Step 3: Enter Profile Name and click OK.

Step 4: Select File System in Publish Method and select your preferred location in the Target Folder.

Step 5: Select Release in Configuration in the next window and click "Next".

Step 6: Click on "Publish" in the next wizard.

You will see that the application will publish successfully.

IIS Host

Open the Internet Information Services (IIS) Manager and follow the procedure given below.

Step 1: Select your Profile in the Default Site.

Step 2: Just click "OK" in the next Add Application wizard.

Step 3: Ensure your Default Site Status is Started in Application Pools.

Step 5: You will see an error such as "This Operation requires IIS integrated pipeline mode" in your browser.

Note: Please don't close the browser.

Step 6: Select "Advanced Settings" of your site in the Application Pool by right-clicking and selecting "Advanced Settings".

Step 7: Select Integrated in the Managed Pipeline Mode.

Step 8: Reload your browser and you will see the Home Page.

Step 9: Now click on "Register" and enter the details.

Summary

So far, this article will help you to learn to create an MVC 5 Application to store the data and information in SQL Server directly and you don't need to worry about creating the database manually. With this article you can also learn to publish your article and browse your application from IIS Manager and the app will run on the IIS Server. So just go for it and let me know if you have any problem.