Top 50 Asp Dot Net Mvc Interview Questions You Must Prepare 14.Jun.2024

No. We can't set unlimited length for property maxJsonLength. Default value is - 102400 and maximum value what we can set would be : 2147483644.

Glimpse is an open source tool for debugging the routes in ASP.Net MVC. It is the client side debugger. Glimpse has to be turned on by visiting to local url link - http://localhost:portname//glimpse.axd This is a popular and useful tool for debugging which tracks the speed details, url details etc.

In Web.Config there are tags called : "ClientValidationEnabled" and "UnobtrusiveJavaScriptEnabled". We can set the client side validation just by setting these two tags "true", then this setting will be applied at the application level.

< add key="ClientValidationEnabled" value="true" />

< add key="UnobtrusiveJavaScriptEnabled" value="true" />

In ASP.Net MVC all public methods have been treated as Actions. So if you are creating a method and if you do not want to use it as an action method then the method has to be decorated with "NonAction" attribute as shown below :

[NonAction]

public void TestMethod()

{

// Method logic

}

HTML Helpers are like controls in traditional web forms. But HTML helpers are more lightweight compared to web controls as it does not hold viewstate and events. HTML Helpers returns the HTML string which can be directly rendered to HTML page. Custom HTML Helpers also can be created by overriding "HtmlHelper" class.

Result of the method : "RenderPartial" is directly written to the HTML response. This method does not return anything (void). This method also does not depend on action methods. RenderPartial() method calls "Write()" internally and we have to make sure that "RenderPartial" method is enclosed in the bracket. Below is the sample code snippet : @{Html.RenderPartial("TestPartialView"); }

Below are the two types of extensions razor view can have :

.cshtml : In C# programming language this extension will be used.

.vbhtml - In VB programming language this extension will be used.

Display Templates : These are model centric. Meaning it depends on the properties of the view model used. It uses convention that will only display like divs or labels.

Edit Templates : These are also model centric but will have editable controls like Textboxes.

Partial View : These are view centric. These will differ from templates by the way they render the properties (Id's) Eg : CategoryViewModel has Product class property then it will be rendered as Model.Product.ProductName but in case of templates if we CategoryViewModel has List then @Html.DisplayFor(m => m.Products) works and it renders the template for each item of this list.

Below are some action filters used :

  • Authentication
  • Authorization
  • HandleError
  • OutputCache

Below is the sample code snippet to add css to razor views : < link rel="StyleSheet" href="/@Href(~Content/Site.css")" type="text/css"/>

Routing is a pattern matching mechanism of incoming requests to the URL patterns which are registered in route table. Class : "UrlRoutingModule" is used for the same process.

Action Filters allow us to execute the code before or after action has been executed. This can be done by decorating the action methods of controls with ASP.Net MVC attributes.

If Tempdata is assigned in the current request then it will be available for the current request and the subsequent request and it depends whether data in TempData read or not. If data in Tempdata is read then it would not be available for the subsequent requests.

Below is the scenario and the solution to solve multiple submit buttons issue. Scenario :

@using (Html.BeginForm("MyTestAction","MyTestController")

{

    <input type="submit" value="MySave" />

    <input type="submit" value="MyEdit" />

} Solution :

Public ActionResult MyTestAction(string submit) //submit will have value either "MySave" or "MyEdit"

{

    // Write code here

}

Yes we can share a view across multiple controllers. We can put the view in the "Shared" folder. When we create a new ASP.Net MVC Project we can see the Layout page will be added in the shared folder, which is because it is used by multiple child pages.

TempData is again a key, value pair as ViewData. This is derived from "TempDataDictionary" class. TempData is used when the data is to be used in two consecutive requests, this could be between the actions or between the controllers. This requires typecasting in view.

PartialView is similar to UserControls in traditional web forms. For re-usability purpose partial views are used. Since it's been shared with multiple views these are kept in shared folder.

Partial Views can be rendered in following ways :

  • Html.Partial()
  • Html.RenderPartial()

"BundleConfig.cs" in ASP.Net MVC4 is used to register the bundles by the bundling and minification system. Many bundles are added by default including jQuery libraries like - jquery.validate, Modernizr, and default CSS references.

Data annotations are attributes which can be found in the "System.ComponentModel.DataAnnotations" namespace. These attributes will be used for server-side validation and client-side validation is also supported. Four attributes - Required, String Length, Regular Expression and Range are used to cover the common validation scenarios.

Model : It is basically a business entity which is used to represent the application data.

Controller : The Request which is sent by the user always scatters through controller and it's responsibility is to redirect to the specific view using View () method.

View : it's the presentation layer of ASP.Net MVC.

ASP.Net MVC is a pattern which is used to split the application's implementation logic into three components i.e. models, views, and controllers.

Yes we can add constraints to route in following ways :

  • Using Regular Expressions
  • Using object which implements interface - IRouteConstraint.

This is a general term that conveys a general philosophy, similar to the term REST (Representational State Trfer). Unobtrusive JavaScript doesn't inter mix JavaScript code in your page markup. Eg : Instead of using events like onclick and onsubmit, the unobtrusive JavaScript attaches to elements by their ID or class based on the HTML5 data- attributes.

TDD is a methodology which says, write your tests first before you write your code. In TDD, tests drive your application design and development cycles. You do not do the check-in of your code into source control until all of your unit tests pass.

"RouteConfig.cs" holds the routing configuration for ASP.Net MVC. RouteConfig will be initialized on Application_Start event registered in Global.asax.

Viewdata contains the key, value pairs as dictionary and this is derived from class : "ViewDataDictionary". In action method we are setting the value for viewdata and in view the value will be fetched by typecasting.

RenderBody is like ContentPlaceHolder in web forms. This will exist in layout page and it will render the child pages/views. Layout page will have only one RenderBody() method. RenderPage also exists in Layout page and multiple RenderPage() can be there in Layout page.

Create a JavaScript method:

function DrpIndexChanged() { } Invoke the method:

< %:Html.DropDownListFor(x => x.SelectedProduct, new SelectList(Model.Customers, "Value", "Text"), "Please Select a Customer", new { id = "ddlCustomers", onchange=" DrpIndexChanged ()" })%>

Below are the advantages of DI :

  • Reduces class coupling
  • Increases code reusing
  • Improves code maintainability
  • Improves application testing

This can be done in following way : Use class : "HttpRequestBase" and use the method : "HttpMethod" to determine the action request type.

View Model is a plain class with properties, which is used to bind it to strongly typed view. View Model can have the validation rules defined for its properties using data annotations.

To create reusable widgets child actions are used and this will be embedded into the parent views. In ASP.Net MVC Partial views are used to have reusability in the application. Child action mainly returns the partial views.

Below are the important namespaces used in ASP.Net MVC :

  • System.Web.ASP.Net MVC
  • System.Web.ASP.Net MVC.Ajax
  • System.Web.ASP.Net MVC.Html
  • System.Web.ASP.Net MVC.Async

ViewBag is a wrapper around ViewData, which allows to create dynamic properties. Advantage of viewbag over viewdata will be : In ViewBag no need to typecast the objects as in ViewData. ViewBag will take advantage of dynamic keyword which is introduced in version 4.@But before using ViewBag we have to keep in mind that ViewBag is slower than ViewData.

When we have created an area make sure this will be registered in "Application_Start" event in Global.asax.

Below is the code snippet where area registration is done :

protected void Application_Start()

{

AreaRegistration.RegisterAllAreas();

}

Razor is the first major update to render HTML in ASP.Net MVC @Razor was designed specifically for view engine syntax. Main focus of this would be to simplify and code-focused templating for HTML generation.

Below is the sample of using Razor:

@model ASP.Net MVCMusicStore.Models.Customer

@{ViewBag.Title = "Get Customers";}

< div class="cust">

@Model.CustomerName

Using this default route - {resource}.axd/{*pathInfo}, we can prevent the requests for the web resources files like - WebResource.axd or ScriptResource.axd from passing to a controller.

Scaffolding in ASP.NET ASP.Net MVC is used to generate the Controllers,Model and Views for create, read, update, and delete (CRUD) functionality in an application. The scaffolding will be knowing the naming conventions used for models and controllers and views.

Below are the types of scaffoldings :

  • Empty
  • Create
  • Delete
  • Details
  • Edit
  • List

We can use dataannotations for validation in ASP.Net MVC. If we want to use validation during runtime using Jquery then we can use Jquery plugins for validation.

Eg:

If validation is to be done on customer name textbox then we can do as :

$('#CustomerName').rules("add", {

required: true,

minlength: 2,

messages: {

required: "Please enter name",

minlength: "Minimum length is 2"

}

});

This can be done in following way : Use class : "HttpRequestBase" and use the method : "HttpMethod" to determine the action request type.

Exception Handling is made simple in ASP.Net MVC and it can be done by just overriding "OnException" and set the result property of the filtercontext object (as shown below) to the view detail, which is to be returned in case of exception.

protected overrides void OnException(ExceptionContext filterContext)

    {

    }

it's a design pattern and is used for developing loosely couple code. This is greatly used in the software projects. This will reduce the coding in case of changes on project design so this is vastly used.

Below is the code snippet to return string from action method :

public ActionResult TestAction() {

return Content("Hello Test !!");

}

It is the process of breaking the program into various distinct features which overlaps in functionality as little as possible. ASP.Net MVC pattern concerns on separating the content from presentation and data-processing from content.

Yes. We can use the razor code in javascript in cshtml by using <text> element.

< script type="text/javascript">

@foreach (var item in Model) {

< text >

//javascript goes here which uses the server values

< text >

}

< script>

This method is used to render the specified partial view as an HTML string. This method does not depend on any action methods.

We can use this like below :

@Html.Partial("TestPartialView")

REST is an architectural style which uses HTTP protocol methods like GET, POST, PUT, and DELETE to access the data. ASP.Net MVC works in this style. In ASP.Net MVC 4 there is a support for Web API which uses to build the service using HTTP verbs.

Layout pages are similar to master pages in traditional web forms. This is used to set the common look across multiple pages. In each child page we can find : /p>

@{

Layout = "~/Views/Shared/TestLayout1.cshtml";

} This indicates child page uses TestLayout page as it's master page.

Name - This is the name of the route.

URL Pattern : Placeholders will be given to match the request URL pattern.

Defaults :When loading the application which controller, action to be loaded along with the parameter.