Top 100+ popular ASP.Net MVC Interview Questions and Answers.

 

Ø  .NET version is released with some significant improvements

o    .NET 1.0 - 2002 Initial version (1st release)

o    .NET 1.1 - 2003 Update on 1.0, added provider for Oracle

o    .NET 2.0 - 2005 Generics were introduced.

o   .NET 3.0 - 2006 WPF, WCF, WF were introduced

o   .NET3.5 - 2007  LINQ and ADO .NET Entity Framework

o    .NET 4.0 - 2010 Dynamic support for languages and TPL (dynamic keyword introduced along with Task Parallel library )

o   . NET 4.5 - 2012 Asynchronous programming support (async and await keyword introduced And Zip facility).

Ø  What is basic authentication?

o   Client send request with user credential in Authorization Header.

o   Credential encrypted with Base 64 encoding and decoding.

o   WWW-Authenticate response header indicates the Basic authentication.

Ø  Disadvantage of Basic Authentication.

o   User sends credential in each and every request so it wills possibility to steal user’s credential.

o   It is implemented by Base 64 Algorithm so this is known algorithm in universal.

Ø  What is JWT(Json Web Tokens) Token?

o   JWT is providing secure data transmission between two parties.

o   Auto generated signed token using mechanism like HMAC, RSA, ECDSA Algorithm.

Ø  Advantage of JWT(Json Web Tokens)

o   When it encoded size is smaller.

o   Use Algorithm like HMAC,RSA,ECDSA for increase more security.

Ø  Disadvantage of JWT?

o   If a user account needs to be blocked or deactivated, the application will have to wait for the token to expire in order for the lockout to be fully effective.

o   Real logout is not possible until token not expire.

o   We could not manually extend expiry time of JWT token, so refresh token and reuse those token is not possible.

Ø  What is ActionResult in MVC?

o   MVC framework contains different result classes when any action returns a result.

Ø  How many type of ActionResult?

o   ViewResult – Return html and markup.

o   EmptyResult – Return no response.

o   ContentResult- Return string literal.

o   RedirectToAction – Return on action method.

o   FileContentResult/FilePathResult/FileStreamResult- Return the content of a file.

o   JavaScriptResult – Return a JavaScript.

o   JsonResult – Return Json.

o   RedirectResult – Redirect on new URL.

o   RedirectToRouteResult – Redirect on another action or another controller.

o   PartialViewResult – Return HTML from partial view.

o   HttpUnauthorizedResult – Return HTTP 403 Status.

Ø  ASP.NET MVC Life cycle.

o   First request URL check in to the routing table.

o   If url found in the routing table, Routing engine forwards the request url to the corresponding IRouteHandler(default is MVCHandler) for that request.

o   MVCHandler is responsible to call the controller using IControllerFactory instance.

o   After controller instantiated, Controller's ActionInvoker identify which specific action to invoke on the controller.

o   The action method process on request, prepare response data and returning a result according to their return result type (for return result type follow our question “How many type of ActionResult?”).

o   View engine (IViewEngine interface) render those action data on view for UI purposes.

Ø  What is routing in ASP.NET MVC?

o   Routing is the pattern matching system, which matches the request URL into the routing table.

o   If the request URL found into the routing table, forward those request to the MVC handler and initiate the request otherwise routing engine returns a 404 HTTP status code.

Ø  Difference between ViewBag and ViewData in ASP.NET MVC.

ü  Both are used for transfer data from controller to view.

ü  ViewData is a Dictionary of objects and accessible by a string key

ü  Ex. ViewData["Result"] = 1;

ü  ViewBag is a dynamic type

ü  Ex. ViewBag.Result=1

ü  View bag is dynamic type so doesn’t require to typecasting.

ü  View data requires typing casting for complex data type and also checking for null to avoid an error.

ü  How to require typecasting let’s see with an example.

Controller:

                     List<string> l = new List<string>() { "1", "3" };

       ViewBag.Result = l;

View:

       @foreach (var item in ViewBag.Result)

                     {

                             <span>@item</span>

       }

 

Controller:

                     List<string> l = new List<string>() { "1", "3" };

       ViewData["Result"] = l;

View:

                     @foreach (var item in ViewData["Result"] as List<string>)

                     {

                           <span>@item</span>

       }

  

Ø  Different types of filters in .Net MVC.

ü  Authorization filters

·         Implements the IAuthorizationFilter.

·         Used to implement Authorization and authentication for controller actions

ü  Action Filters

·         Implements the IActionFilter.

·         Perform some operation or task before and after an action method executes.

ü  Result Filters

·         Implements the IResultFilter.

·         Perform some operation or task before or after the executions of the view.

ü  Exception Filters

·         Implements the IExceptionFilter.

·         Perform some operation or task when any unhandled error occurred during the ASP.NET MVC pipeline.

 Ø  Is it possible to invoke Garbage Collector explicitly?

ü  Yes using System.GC.Collect();

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