ASP.NET MVC 4 New Features Interview Questions

1. Articles from Jinal Desai .NET
ASP.NET MVC 4 New Features Interview Questions
2013-06-27 06:06:40 Jinal Desai
1. What is main focus of ASP.NET MVC 4?
Ans. The main focus of ASP.NET MVC 4 is making it easier to develop mobile web
applications. Other than mobile web applications it’s focus is also on better HTML5
support and making ASP.NET MVC web application cloud ready. Using new
features of ASP.NET MVC 4 you can develop web applications that can work well
across different mobile devices and desktop web browsers.
2. What is ASP.NET Web API?
Ans. ASP.NET Web API is a framework for building and consuming HTTP Services.
It supports wide range of clients including browsers and mobile devices. It is a great
platform for developing RESTful services since it talks HTTP.
3. You can also develop RESTful services using WCF, then why this new
framework Web API?
Ans. Yes we can still develop RESTful services with WCF, but there are two things
that prompt users to use ASP.NET Web API over WCF for development of RESTful
services. First one is ASP.NET Web API is included in ASP.NET MVC which
obviously increases TDD approach in the development of RESTful services.
Second one is for developing RESTful services in WCF you still needs lot of
configurations, URI templates, contracts and endpoints which developing RESTful
services using ASP.NET Web API is simple.
4. What are the enhancements done in default project template of ASP.NET
MVC 4?
Ans. The enhanced default project template is modern-looking. Along with cosmetic
enhancements, it also employs adaptive rendering to look nice in both desktop and
mobile browsers without need of any kind of additional customization.
5. Why separate mobile project template while you can render your web
application in mobile without additional customization?
Ans. The mobile project template touch-optimized UI using jQuery.Mobile.MVC
NuGet Package for smart phones and tablets.
6. What is Display Modes?
Ans. Display Modes is new feature provided in ASP.NET MVC 4. It lets an
application select views depending on the browser which is making request. For
example, if a desktop browser requests home page of an application it will return
ViewsHomeIndex.cshtml view and if a mobile browser requests home page it will
return ViewsHomeIndex.mobile.cshtml view.
7. Does ASP.NET MVC 4 supports Windows Azure SDK?
Ans. Yes, ASP.NET MVC 4 supports Windows Azure SDK version 1.6 or higher.

2. 8. What is Bundling and Minification feature provided in ASP.NET MVC 4?
Ans. It reduces number of HTTP requests that a web page needs to make. Bundling
and Minification combines individual files into single, bundled file for scripts and CSS
and then reduce the overall size by minifying the contents of the bundle.
9. While developing application using ASP.NET MVC 4, I want to provide
authentication using popular sites like Facebook or twitter into my web
application, is it possible in ASP.NET MVC 4?
Ans. Yes, using DotNetOpenAuth library we can provide authentication using OAuth
or OpenID providers. In ASP.NET MVC 4 Internet project template includes this
library.
10. What’s the difference between Empty MVC Project template in ASP.NET
MVC 3 and ASP.NET MVC 4?
Ans. The ASP.NET MVC 4 Empty project template is really empty. It does not
contain any css and js files as compared to previous Empty project template, which
contains all these files.
11. What are the main features of ASP.NET MVC used by ASP.NET Web API?
Ans.
Routing: ASP.NET Web API uses same convention for configuration mapping that
ASP.NET MVC provides.
Model Binding and Validation: ASP.NET Web API uses same model binding
functionality, but tailored to HTTP specific context related operations only.
Filters: The ASP.NET Web API uses lots of filters built-in MVC.
Unit Testing: Now it’s based on MVC, truly unit testable.
12. If I want to create resource oriented services that can use full features of
HTTP like cache control for browsers, use URI templates to include Task
URIs in your responses, versioning and concurrancy using ETags, pass
various content types such as images, documents, HTML pages etc. then
which is preferred for development of services, WCF or Web API?
Ans. In such scenario Web API would be preferred choice. Using Web APIs we can
develop services which utilizes full features of HTTP.
13. Suppose I want to develop services which supports special scenarios
like one way messaging, duplex communication, message queues, ete then
which is the best way to develop services, WCF or Web API?
Ans. In this scenario WCF suits the requirement. WCF provides all kine of
messaging facility.
14. Now, if I want to create services which are exposed over various
transport channels like TCP, Named Pipe or even UDP. I also want the
support of HTTP transport channel when other transport channels are
unavailable then which is the preferred way, WCF or Web API and why?
Ans. For such scenario WCF is preferred way for development of services because
WCF support almost all kind of transport mechanism and we need to expose
SOAP-based and WebHTTP-based bindings.

3. 15. What is the difference between asynchronous controller implementation
between ASP.NET MVC 3 and ASP.NET MVC 4? Can you explain in detail?
Ans. There is large difference between the working and implementation mechanism
between ASP.NET MVC 3 and ASP.NET MVC 4.
In ASP.NET MVC 3, to implement asynchronous controller/methods you need to
derive controller from AsyncController rather than from plain Controller class. You
need to create two action methods rather than one. Fist with suffix “Async” keyword
and second with “Completed” suffix. The method which initiated asynchronous
process must end with “Async” and the method which is invoked when the
asynchronous process finishes must end with “Completed”. Following is example
showing the same.
//Synchronous Implementation
public class SynchronousTestController : Controller
{
public ActionResult Index()
{
method1();
method2();
return View();
}
}
//Asynchronous Implementation in ASP.NET MVC 3
public class AsynchronousTestController : AsyncController
{
public void IndexAsync()
{
method1();
method2();
}
public ActionResult IndexCompleted()
{
return View("Index");
}
}
The ASP.NET MVC 4 Controller class in combination .NET 4.5 enables you to write
asynchronous action methods that return an object of type Task. The .NET
Framework 4 introduced an asynchronous programming concept referred to as a
Task and ASP.NET MVC 4 supports Task. The .NET Framework 4.5 builds on this
asynchronous support with the await and async keywords that make working with
Task objects much less complex than previous asynchronous approaches. The
await keyword is syntactical shorthand for indicating that a piece of code should
asynchronously wait on some other piece of code. The async keyword represents a
hint that you can use to mark methods as task-based asynchronous methods. To
implement asynchronous action method in ASP.NET MVC 4 we do no need to
derive our controller class from AsyncController, async and await in cooperation

4. with Task will do the magic. To mark the action method asynchronous use async in
method signature. To wait for the other method to finish use await and to call
multiple parallel methods use Task. The asynchronous method will return Task
instead of plain ActionResult.
public class AsyncronousTestController : Controller
{
public async Task<ActionResult> IndexAsync()
{
//if single method
//await method();
//if multiple methods
await Task.WhenAll(method1(), method2());
return View("Index");
}
}
Here the await keyword does not block the thread execution until the task is
complete. It signs up the rest of the method as a callback on the task, and
immediately returns. When the awaited task eventually completes, it will invoke that
callback and thus resume the execution of the method right where it left off.
16. Can you tell us some guidelines for when to use synchronous and when
to use asynchronous approach?
Ans. In following situations synchronous approach is more suited.
1. The operations are simple or short-running.
2. Simplicity is more important than efficiency.
3. The operations are primarily CPU operations instead of operations that involve
extensive disk or network overhead. Using asynchronous action methods on
CPU-bound operations provides no benefits and results in more overhead.
For asynchronous approach some of the guidelines are
1. You’re calling services that can be consumed through asynchronous
methods, and you’re using .NET 4.5 or higher.
2. The operations are network-bound or I/O-bound instead of CPU-bound.
3. Parallelism is more important than simplicity of code.
4. You want to provide a mechanism that lets users cancel a long-running
request.
5. When the benefit of switching threads out weights the cost of the context
switch. In general, you should make a method asynchronous if the
synchronous method waits on the ASP.NET request thread while doing no
work. By making the call asynchronous, the ASP.NET request thread is not
stalled doing no work while it waits for the web service request to complete.
6. Testing shows that the blocking operations are a bottleneck in site
performance and that IIS can service more requests by using asynchronous
methods for these blocking calls.

5. 17. Which latest version of Entity Framework is included by ASP.NET MVC 4?
What is the advantage of it?
Ans. ASP.NET MVC 4 is included Entity Framework 5. The main advantage of Entity
Framework 5 is it’s new feature called database migration. It enables you to easily
evolve your database schema using a code-focused migration while preserving the
data in the database.
18. What is ASP.NET MVC 4 recipe? Can you explore something on recipes?
Ans. In technical language ASP.NET MVC 4 recipe is nothing but a dialog box that is
delivered via NuGet with associated UI and code used to automate specific task. It’s
like GUI for NuGet Package Manager. Recipes are set of assemblies which are
loaded dynamically by Managed Extensibility Framework (MEF). MEF provides
plugin model for applications. The main use of recipes are to automate development
task, tasks that are encapsulated into recipes and used over and over again. For
example, adding ajax grid to view or manipulating multiple areas of the application
can be automated using ASP.NET MVC 4 recipes.
18. What are the provisions for real time communication in ASP.NET MVC 4?
Ans. ASP.NET MVC 4 supports WebSockets along with the new open source
framework SignalR which allows to set up real time multi-user communication
through open TCP sockets.
19. What is the enhancement provided related to custom controller in
ASP.NET MVC 4?
Ans. In ASP.NET MVC 4 you can place custom controller to custom locations. In
ASP.NET MVC 3 you can only place custom controllers inside the Controllers folder.