Top 30+ ASP.NET Interview Questions and Answers

Particularly for positions requiring proficiency in ASP.NET MVC, ASP.NET Core, C#, SQL Server, and front-end technologies, ASP.NET developers are in high demand. In this article, we have compiled the top 30+ ASP.NET interview questions and answers to help you get success. Get started with our exclusive ASP.NET course syllabus.

ASP.NET Interview Questions for Freshers

Here are the basic ASP.NET interview questions for freshers.

1. What is a web application?

An application that enables users to communicate with a web server via a web browser without the need to install it is known as a web application. 

• The way it operates: A web application consists of two components: the client, which is often the browser, and the web server. Over a network, the components exchange information, frequently via the HTTP protocol.
• Benefit: Many computers and operating systems can run web applications, and they don’t take up any hard drive space.  
• Examples: Google Docs, Gmail, Facebook, Twitter, Amazon, and Netflix.

2. What is ASP.NET?

A framework called ASP.NET is used to create web apps using HTML, CSS, and JavaScript. It is a component of the.NET Framework, a platform for developers that consists of libraries, programming languages, and tools.

3. What is the use of ASP.NET?

A range of apps can be created with ASP.NET, such as:

• Websites and web applications.
• Internet of Things (IoT) apps.
• Mobile backends.
• Accounting and finance applications.
• Manufacturing process control dashboards.
• Client management systems.

4. How ASP.NET works?

Three frameworks are available in ASP.NET for creating web applications:

• Web Forms: A drag-and-drop approach to creating dynamic webpages is Web Forms.
• ASP.NET MVC: A framework for creating dynamic websites based on patterns
• ASP.NET Web Pages: Create dynamic web content by fusing HTML with server code. 

5. Which programming languages are compatible with ASP.NET development?

Languages supported by ASP.NET include C#, VB.NET, and, originally, J#.

6. How to code with ASP.NET and where it runs?

Any language that is compatible with the common language runtime (CLR), such as Microsoft Visual Basic, C#, JScript.NET, and J#, can be used to code ASP.NET applications. 

Docker, Windows, Linux, and macOS can all run ASP.NET because it is cross-platform.  

7. When creating ASP.NET web apps, which IDE is utilized?

The official IDE that fully supports ASP.NET web apps is Visual Studio.

ASP.NET web applications can be developed with Visual Studio Community Edition, a free IDE (Integrated Development Environment). It includes a range of features and tools to boost development and improve applications.

Additional tools for ASP.NET development include the following:

• Chocolatey: A Windows NT software package manager and execution engine that makes use of Windows PowerShell and NuGet packaging technology.
• LINQPad: One tool for testing code and querying databases is called LINQPad.
• JetBrains Rider: A cross-platform.NET integrated development environment (IDE) that works with Windows, Linux, MacOS, and other operating systems.  

8. What are the common features of ASP.NET?

ASP.NET is a framework for developing web applications with numerous capabilities, such as: 

• Cross-platform.
• High performance.
• Language-neutral.
• Developer-friendly environment.
• Built-in security.
• Seamless integration.
• Model View Controller (MVC).
• Action filters.
• Model binding.
• Windows identity.

9. Which is the latest version of ASP.NET?

Version 8.0.0, the most recent stable release of ASP.NET Core, was made available on November 14, 2023.  

ASP.NET Core can be installed on your own Linux or Windows servers, any major cloud platform, and a variety of hosting companies.

10. Is ASP.NET backend or frontend?

It provides an organized, object-oriented method for creating server-side web applications and is mostly utilized for back-end web development. Front-end functionality is usually done using distinct technologies like HTML, CSS, and JavaScript, whereas ASP.NET MVC manages the back-end logic.

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ASP.NET Interview Questions for Intermediate

11. What distinguishes ASP.NET MVC from ASP.NET Web Forms?

While ASP.NET MVC employs a model-view-controller paradigm that divides responsibilities and enhances testability, ASP.NET Web Forms builds web applications using a page-based model.

ASP.NET Web Forms and ASP.NET MVC differ in the following ways:

• URLs: ASP.NET MVC employs route-based URLs, whereas ASP.NET Web Forms utilizes file-based URLs.
• Flexibility: Both during design and during execution, ASP.NET Web Forms offer versatility.
• Code: ASP.NET Web Forms enables code to be written independently of the controls in a different file.
• Page lifecycle: Because ASP.NET MVC has a shorter page lifecycle, it is simpler and easier to comprehend.
• Customization: By granting developers greater authority over HTML, JavaScript, and CSS, ASP.NET MVC facilitates accessibility and customization.
• Programming interface: The well-defined programming interface of ASP.NET MVC facilitates testability.
• Separation of concerns: This is enforced by ASP.NET MVC.
• Loosely coupled classes: ASP.NET MVC requires that classes be created that are less reliant on one another.

A web development framework called ASP.NET MVC aids programmers in creating dynamic websites and online apps.  

12. What distinguishes ASP.NET Core from ASP.NET?

While ASP.NET Core is a cross-platform, high-performance framework for creating contemporary, cloud-based, and internet-connected apps, ASP.NET is a framework for creating web applications on the .NET Framework.

• Architecture: The architecture of ASP.NET Core is modular, whereas that of ASP.NET is monolithic. As developers can only include the components they require, ASP.NET Core applications are therefore lighter and more efficient.
• Compatibility: While ASP.NET Core can operate on Windows, macOS, and Linux, ASP.NET apps usually need a Windows server environment.
• Deployment: Cloud services such as Google Cloud Platform, AWS, and Microsoft Azure can host ASP.NET Core apps.
• Support: ASP.NET will only receive security updates while Microsoft concentrates its future development efforts on ASP.NET Core.
• Ecosystem: While ASP.NET Core is expanding and becoming more popular, ASP.NET has a broader ecosystem with more libraries and community support.
• Use cases: For projects and legacy applications that require integration with the entire.NET Framework, ASP.NET is a suitable option. For cloud-based apps, enterprise projects, and situations requiring lightweight, high-performance web development, ASP.NET Core is a solid option.

13. Define ViewState in ASP.NET.

A hidden field called ViewState is used to save a web page’s state between postbacks. Web pages may save and preserve values in between requests without depending on the server state because of ASP.NET’s ViewState feature.

• What it does: It holds values, such as control settings and page or control property values, that must be maintained between postbacks.
• How it operates: The client sends the view state back to the server as part of a postback after ASP.NET delivers it to them as a hidden field in a form.
• When to apply it: Values can be maintained between postbacks using view state instead of being saved in session state or a user profile.
• How to disable it: Although you can disable the view state, there are several situations where you might want to do so.

To store view state data in an SQL Server database or another data store, you may also construct a custom view state provider.  

14. What is the ASP.NET Global.asax file used for?

Code for reacting to application-level events that ASP.NET raises is contained in the Global.asax file. In ASP.NET, the Global.asax file is used to handle high-level application events and carry out additional functions like:

• Handling application events: Events such as application start and application error can be handled using the Global.asax file.
• Initializing variables: Variables can be initialized using the Global. asax file.
• Controlling page access: Page access can be managed using the Global.asax file.
• Including functions: You can include functions in the Global.asax file.
• Containing TypeLibrary declarations: TypeLibrary declarations may be included in the Global.asax file.

15. What distinguishes Response.Redirect from Server.Transfer?

While Response. Redirect sends a fresh request to the client browser, and Server.Transfer maintains the execution on the server side. They used to transfer users across web pages but they are different in a few ways: 

• Redirect URL:  Response.Redirect ends the current page and launches a new one with a given URL path. Server.Transfer redirects a request to a new URL. 
• Number of requests: Response.Redirect often needs two requests: one to the page that was redirected and one to the original page. Server.Transfer just needs to send the server one request. 
• User awareness: The user is aware that Response.Redirect is taking them to a different page. Because the URL in the browser remains unchanged, the user is not aware of the transfer with Server.Transfer.
• Speed: The extra round trip causes Response.Redirect to be slower. In comparison, Server.Transfer is quicker. 
• Query string value: Response.Redirect does not preserve the value of the query string. Server.Transfer preserves the value of the query string.
• Navigable pages: Server.Transfer can only access pages that have an ASX extension and are hosted on the same server.

As it eliminates the need for an additional round trip, Server.Transfer is a more effective option than Response.Redirect. 

16. What is a session in ASP.NET?

A server-side object called a session keeps track of how a user interacts with the online application. A session in ASP.NET is a means of storing and retrieving user information as the user navigates an online application.

• How it operates: Its session state saves user information in a store that the application maintains and keeps track of throughout client requests.
• Why it’s beneficial: Because HTTP is a stateless protocol—that is, a web server handles each request for a page as independent—ASP.NET session state is helpful.
• How it is made possible: All ASP.NET apps have ASP.NET session state enabled by default.
• How to turn it off: Setting the allowSessionState property to false will disable the ASP.NET session state.
• How it is built: The foundation of the ASP.NET session state is IDistributedCache, which your application can use as a more versatile cache.  

17. What is PostBack in ASP.NET?

The process by which a web page returns data to the same page on the server is known as postback. It makes it possible to continue interacting with the user after a page reload.

• Sending an ASP.NET page to a server for processing is known as a postback in ASP.NET. 
• The client (browser) travels back and forth between the server and the client. 
• When specific page credentials need to be verified against sources, like a database, a postback is executed.
  • For example, a postback can be used to confirm a password and username.  
• A read-only Boolean property called IsPostBack tells you if a page or control is loading for the first time or in response to a postback. 
• By using this feature, expensive processes like populating ListItems or retrieving data from a database can be avoided.  

The control settings of the ASP.NET page framework are maintained between post-backs and sessions via the view state.

18. What is the purpose of the web.config file in ASP.NET?

The configuration file called web.config is used to manage and handle various settings of ASP.NET applications like database connections, custom error pages, and session states.

It is used to perform the following things:

• Configure application behavior: The web.config file explains how ASP.NET applications behave.
• Edit configuration data: We can update the web.config file before, during, and after the application deployment.
• Separate configuration data from code: The Web.config file keeps application configuration settings separate from the application code. This simplifies the associate settings with applications and updates settings after deployment.
• Set configuration settings on a per-directory basis: We can use the <location> element in the Web.config file to specify settings for a specific application or directory. 

19. How to create a web.config file in ASP.NET?

The web.config file can be created as follows:

• Using a text editor like Notepad.
• Create a text file named Web.config in the root directory of your ASP.NET application.
• Ensuring the file is a well-formed XML document. 

You can also edit ASP.NET configuration files using the ASP.NET MMC snap-in, the Web Site Administration Tool, or the ASP.NET configuration API. 

20. What is the role of the IActionResult interface in ASP.NET MVC?

In ASP.NET MVC, the IActionResult interface establishes the contract for the action method’s result. It supports a variety of action results, including views, JSON data, and file downloads.

• ActionResult: A controller method’s return type is represented by an abstract class. Action outcomes might reroute to other controllers, file streams, or return models to views. 
• Return Types: BadRequestResult (400), NotFoundResult (404), and OkObjectResult (200) are a few examples of common action result return types.  
• Convenience techniques: Action result types can be returned from an action using the convenience methods in the ControllerBase class.
  • For example, return new BadRequestResult(); can be shortened to return BadRequest();.  
• ProducesResponseType attribute: For web API help pages, this feature can be used to generate more detailed response data. It lists the HTTP status codes and known kinds that the activity will return. 

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21. What is a master page in ASP.NET?

Multiple web pages in an application can have a consistent layout due to master pages. They have controls and markup shared by several content pages. In ASP.NET, a master page is a file that specifies the structure and appearance of a website or web application. 

• It may contain HTML elements, server controls, and static text. 
• The file extension is .master, and the @Master directive designates the master page. 

A master page in ASP.NET can be used for the following purposes:

• Control the layout: The layout of a website or web application, including the <html>, <head>, and <body> tags, can be specified by a master page.
• Define the look and feel: An application’s appearance and feel, including the placement of various content placeholders, can be specified by a master page.  
• Create content pages: An ASP.NET web page linked to a master page is called a content page.
  • Only the text and controls that are merged with the ContentPlaceHolder controls on the master page during runtime are included in the content page.

By adding the relevant directive to a blank page, you can build a content page. If you are editing a master page, you may also use a shortcut to create a content page.  

22. What is ASP.NET’s Page Life Cycle?

Stages including initialization, loading, rendering, and unloading are all part of the page life cycle. Developers can add custom logic and control the status of controls and pages at each level.

Understanding the page life cycle is crucial because it enables developers to write code at the right moment to produce the intended result. 

For instance, to properly initialize controls and fill control attributes with view-state data, developers must comprehend the page life cycle.  

The following information relates to the life cycle of an ASP.NET page:

• Page request: The server receives a page request from a user, processes it, builds the page, and replies.
• Cache: The cache determines whether the output already exists if the page is requested more than once.
• Postback: The data is sent to the server and then posted back to the viewer when a user clicks on an event on the page.
• Cycle: Every time the web page is altered, the complete cycle is repeated.  

23. What is Razor in ASP.NET?

Razor is a markup syntax that allows dynamic online content to be created in ASP.NET MVC and ASP.NET Core by inserting server-based code into webpages.

How it works: Before sending the page to the browser, the server executes the code when a web page with Razor syntax is called. The programming can dynamically generate information and carry out intricate operations like database access.  

File extensions: File extensions ending in.cshtml or.vbhtml are commonly used for Razor syntax files.

Syntax: Razor syntax consists of:

• Razor code blocks: Enclosed in @{ … } 
• Inline expressions: Start with @ 
• Code statements: End with a semicolon 
• Variables: Declared with the var keyword 
• Strings: Enclosed with quotation marks 

Base classes: A component’s base class can be specified using the @inherits directive. This makes it possible for a collection of components to inherit C# code.  

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24. How are states handled in ASP.NET applications?

Various methods, including ViewState, SessionState, ApplicationState, Cookies, and QueryStrings, can be used to handle states in ASP.NET.

The process of preserving an object’s or variable’s state across the course of a page’s existence is known as state management. In ASP.NET, state management comes in two varieties:

• Client-side state management: It stores information as hidden fields or cookies in the client’s browser.
• Server-side state management: Keeps information on the server in the form of session or application states.

Although it can utilize more server resources, server-based state management can decrease the quantity of data transmitted to the client. 

25. What is the purpose of the “using” statement in C# with ASP.NET?

By automatically invoking the Dispose method on objects that implement the IDisposable interface, the “using” statement guarantees that resources are disposed of appropriately.

In C#, the using statement serves several functions, such as: 

• Ensuring correct use of disposable objects: Even in the event of an exception, the using statement guarantees that disposable items are used and disposed of appropriately.
• Importing namespaces: They can be imported at the beginning of a code file using the using statement. 
• Defining a scope: Any variables specified are confined to the scope block defined by the using statement.
• Creating aliases: An alias for a type or namespace can be created using the using statement. 

When working with resources that implement the IDisposable interface, like file handles or network connections, the using statement comes in handy. When you’re finished using these resources, you must release them.  

26. What are the benefits of the ASP.NET Web API?

A framework called ASP.NET Web API is used to provide HTTP services that may be used by a variety of clients, such as mobile devices and browsers. It facilitates the development of scalable and maintainable web services and supports RESTful services.

ASP.NET Web API offers numerous advantages, such as:

• Supports multiple response data formats: Multiple response data formats are supported by the ASP.NET Web API, including XML, JSON, and BSON formats.
• Perfect for native apps: When developing native apps for mobile devices, ASP.NET Web API is a solid option.
• Ideal for Ajax-based web applications: When developing web applications that rely on AJAX, the ASP.NET web API is a solid option.
• Lightweight and modular: Developers have more control over their apps due to ASP.NET Core’s lightweight design and modular architecture.
• Side-by-side versioning: Modern web development is made easier with side-by-side versioning.
• Simple configuration: WCF requires more configuration than ASP.NET Web API.
• Best option for lighter, simpler services: For lighter, simpler services, the ASP.NET Web API is a superior option.  

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ASP.NET Experienced Interview Questions and Answers

27. In Visual Studio, how do you start a new ASP.NET project?

To configure our project, launch Visual Studio, click “Create a new project,” pick “ASP.NET Core Web Application,” and then follow the instructions.

We can begin a new Visual Studio ASP.NET project by: 

• Open Visual Studio 
• Select Create a new project 
• Choose the ASP.NET Core Web App template 
• Enter a name for your project 
• Select Next 
• Choose the desired .NET version in the Additional Information dialog. 
• Select Create 

Another way to start a new project:

• Selecting File > New > Project from the menu bar
• Selecting the New Project button on the toolbar
• Pressing Ctrl+Shift+N 

All of the template files required to create a website are included in the ASP.NET Core project type.

28. What function does an ASP.NET Core application’s Startup class serve?

The application and its services are configured using the Startup class. It includes middleware and dependency injection setup techniques such as ConfigureServices and Configure.

An ASP.NET Core application’s Startup class serves as its entry point, setting up configuration and wiring up services. It is the control center of the application, where services and the request pipeline are set up. Because it makes sure the program is properly configured before it begins to serve HTTP requests, the Startup class is crucial.  

The following methods are part of the Startup class:

• ConfigureServices: It sets up the services provided by the application. Services are reusable parts that give a program capability.
• Configure: It builds the request processing pipeline for the application. This method is called by the runtime right after the ConfigureServices method.

Additionally, a constructor in the Startup class initializes an instance of IConfiguration.  

Example:

namespace WebStartup.Middleware;

// <snippet1>

public class RequestSetOptionsStartupFilter : IStartupFilter

{

    public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)

    {

        return builder =>

        {

            builder.UseMiddleware<RequestSetOptionsMiddleware>();

            next(builder);

        };

    }

}

// </snippet1>

29. In ASP.NET Core, how are exceptions handled?

To catch exceptions and deal with them properly, use the try-catch block. Additionally, middleware can be used to universally catch and log exceptions.

The built-in exception handler middleware in ASP.NET Core uses IExceptionHandler implementations to handle exceptions. The middleware uses the original HTTP method to re-execute the request.

To incorporate an IExceptionHandler implementation into the ASP.NET Core request pipeline, follow these steps:

• Use dependency injection to register the IExceptionHandler service.
• Integrate the request pipeline with the ExceptionHandlerMiddleware.

The ASP.NET Core pipeline tries to handle the supplied exception using the TryHandleAsync function. The method returns false if the exception cannot be handled and true if it can.  

Only those HTTP methods will cause an error handler endpoint to operate if it is limited to a particular range of methods. An MVC controller action that employs the [HttpGet] attribute, for instance, will only execute in response to GET requests.  

Sample Program for Exception Handling in ASP.NET

class HandledException {

  public static void Main() {

    int x = 0;

    int intTemp = 0;

    try {

      intTemp = 100/x;

      Console.WriteLine(“Not executed line”);

    }

    catch(Exception e) {

      Console.WriteLine(“oException” );

    }

    Console.WriteLine(“Result is {0}”, intTemp);

  }

}

30. In ASP.NET Core MVC, how do you create a controller?

To build a new controller, use the Controllers folder’s AddController function. A controller with CRUD operations can also be created using Visual Studio’s scaffolding capability.

In ASP.NET Core MVC, you can create a controller by:

• Right-clicking Solution Explorer’s Controllers folder
• Select Controller after clicking Add.
• In the dialog box for adding scaffold, choose MVC Controller – Empty.
• Click “Add.”
• Click Add after giving your new controller a name.  

Another option is to manually construct a controller class:

• Select the Controllers folder with a right-click.
• Choose Add and then New Item.
• Choose the template for the class.
• Click Add after giving the new class a name.
• Modify the resulting class file so that the class inherits from the base “System.Web.Mvc.Controller” class 

A controller’s public methods can all be called HTTP endpoints. A web application’s targetable URL is known as an HTTP endpoint.  

Sample Program to Create Controller in ASP.NET

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcApplication1.Controllers

{

    public class PersonController : System.Web.Mvc.Controller

    {

        public string Index()

        {

            return “Hello World!”;

        }

    }

}

31. What function does Entity Framework’s DbContext class serve?

The main class in Entity Framework for interacting with the database is DbContext. It configures the model for data storage and querying and controls the database connection.

Entity Framework’s DbContext class controls a database connection and monitors modifications to model classes:

• Connection management: Database connections are managed by the DbContext, which opens and closes them as necessary.
• Data retrieval and saving: Data can be saved to and retrieved from the database by the DbContext.
• Change tracking: Before entities are saved to the database, the DbContext keeps track of and regulates any modifications made to them.
• Encapsulating database logic: Working with the database is made simpler by the DbContext, which encapsulates database logic within the application.  

When the DbContext instance is no longer required, resources are released via the Dispose function of the DbContext class, which implements the.NET IDisposable interface. 

When the DbContext instance is no longer required, you can call the Dispose method or utilize the utilizing pattern to make sure that resources are cleaned up.  

Sample for DbContext: Code 1: BreakAwayContext that inherits from ObjectContext

public class BreakAwayContext : ObjectContext

{

  private ObjectSet<Person> _ people;

  private ObjectSet<Destination> _destinations;

  private ObjectSet<Trip> _trips;

  public ObjectSet<Person> People

  {

    get { return _people ?? (_people = CreateObjectSet<Person>(“People”)); }

  }

  public ObjectSet< Destination > Contacts

  {

    get { return _ destinations?? (_destinations =

              CreateObjectSet< Destination >(“Destinations”)); }

  }

  public ObjectSet<Trip> Trips

  {

    get { return _ trips?? (_trips = CreateObjectSet<Trip>(“Trips”)); }

  }

}

Code 2: BreakAwayContext that inherits from DbContext

public class BreakAwayContext : DbContext

  {

    public DbSet<Person> People { get; set; }

    public DbSet<Destination> Destinations { get; set; }

    public DbSet<Trip> Trips { get; set; }

}

32. In ASP.NET Core MVC, how are CRUD operations carried out?

To manage Create, Read, Update, and Delete operations, use the controller actions. Entity Framework can be used to communicate with databases and return JSON responses or views.

In ASP.NET Core MVC, you may carry out CRUD tasks by:

• Add data models: Choose Add with a right-click on Models, then Class.
• Add validation: To render form inputs and show validation messages, use the Tag Helpers asp-for and asp-validation-for.
• Choose to manage NuGet packages: Select Manage NuGet Packages, select the Browse tab, type “Microsoft.EntityFrameworkCore.Tools”, and press Enter.
• Scaffold CRUD operations: The MVC scaffolding automatically generates CRUD (create, read, update, and delete) code in controllers and views; you can modify it.

Create, Read, Update, and Delete is what CRUD stands for. Any database’s data can be subjected to these four fundamental processes.  

Sample Program for CRUD Operations in ASP.NET MVC

@model IEnumerable<CrudOperationInMVC.Controllers.Employee>

@{

    ViewBag.Title = “Index”;

}

<p>Index</p>

<p class=”text-right”>

    @Html.ActionLink(“Create New”, “Create”)

</p>

@if (ViewBag.Message != null)

{

<p class=”alert alert-success” role=”alert”>

    @ViewBag.Message

</p>

}

<table class=”table”>

    <tr>

        <th>

            @Html.DisplayNameFor(model => model.EmployeeName)

        </th>

        <th>

            @Html.DisplayNameFor(model => model.EmployeeSalary)

        </th>

        <th>

            @Html.DisplayNameFor(model => model.EmployeeCity)

        </th>

        <th></th>

    </tr>

    @if (Model != null && Model.Count() > 0)

    {

        foreach (var item in Model)

        {

            <tr>

                <td>

                    @Html.DisplayFor(modelItem => item.EmployeeName)

                </td>

                <td>

                    @Html.DisplayFor(modelItem => item.EmployeeSalary)

                </td>

                <td>

                    @Html.DisplayFor(modelItem => item.EmployeeCity)

                </td>

                <td>

                    @Html.ActionLink(“Edit”, “Edit”, new { id = item.EmployeeId }) |

                    @Html.ActionLink(“Details”, “Detail”, new { id = item.EmployeeId }) |

                    @Html.ActionLink(“Delete”, “Delete”, new { id = item.EmployeeId })

                </td>

            </tr>

        }

    }

    else

    {

        <td colspan=”4″ class=”text-center”><b>No Data Available . Please Add Data By CLick On Create Button</b></td>

    }

</table>

33. What function does the View serve in ASP.NET MVC?

Rendering the user interface is the responsibility of the View in MVC. It uses Razor syntax and HTML to manage user interactions and show data.

Presenting the user interface (UI) and managing user interaction with the application’s data are the responsibilities of the view in the ASP.NET MVC framework.

What it is: A view is a Razor-enabled HTML template that uses the model’s data to produce the final page.

How it operates: The controller gives it the model and chooses which view to show. The page is then rendered by the view.

How it’s applied: For instance, depending on the items’ and objects’ current status, an edit view of an item table may show text boxes, pop-ups, and checkboxes.  

The Model-View-Controller (MVC) paradigm, which is used by the ASP.NET MVC framework, divides a program into three discrete parts:

• Model: Shows the data and business entities of the application.
• View: Manages user interaction and displays the application’s user interface.
• Controller: It decides what response to send back to the user and regulates how the user interacts with the application.

Separation of concerns is facilitated by the MVC pattern.  

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34. How do you implement authentication in ASP.NET Core?

To configure authentication, use ASP.NET Core Identity. Use middleware to enforce authorization and authentication, and configure the services in the Startup class.

The following actions can be taken: 

Step 1: Create a web app. Select File > New > Project > ASP.NET Core Web Application.

Step 2: Select authentication. Choose Change Authentication and then Individual User Accounts.

Step 3: Install packages. Install the following: 

• Microsoft.AspNetCore.Identity.EntityFrameworkCore 
• Microsoft.AspNetCore.Identity.UI

Step 4: Update AppDbContext.

• Update your AppDbContext class to inherit from IdentityDbContext<IdentityUser>

Step 5: Add middleware. Add authentication middleware.

Step 6: Migrate and update the database. Migrate and update the database.

Step 7: Configure authentication. Open the appsettings.json file and replace the existing code.

Step 8: Register authentication services. Register authentication services in Startup.ConfigureServices.

Step 9: Add authentication middleware: Call UseAuthentication in Startup.Configure.

By turning on basic authentication in IIS Manager and giving controller operations that require authentication of the [Authorize] attribute, you may also apply basic authentication to the ASP.NET Web API.

Authorization is the process of figuring out what a user is allowed to do, whereas authentication is the process of confirming a user’s identity.  

35. What is the ASP.NET MVC ModelState used for?

The user-submitted form fields’ current state is represented by the ModelState. Validation mistakes are shown in the view and user input is validated.

Sample Program: AddMovieM:

namespace ModelStateCoreDemo.ViewModels

{

    public class AddMovieVM

    {

        public string Title { get; set; }

        public DateTime ReleaseDate { get; set; }

        public int RuntimeMinutes { get; set; }

    }

}

Additionally, we’ll make a matching Add.cshtml view in the Views/Movie folder:

@model ModelStateCoreDemo.ViewModels.AddMovieVM

<h2>Add Movie</h2>

<form asp-action=”AddPost” asp-controller=”Movie” method=”post”>

    <div>

        <div>

            <label asp-for=”Title”></label>

            <input type=”text” asp-for=”Title” />

        </div>

        <div>

            <label asp-for=”Description”></label>

            <input type=”text” asp-for=”Description” />

        </div>

        <div>

            <label asp-for=”ReleaseDate”></label>

            <input type=”date” asp-for=”ReleaseDate” />

        </div>

        <div>

            <label asp-for=”RuntimeMinutes”></label>

            <input type=”number” asp-for=”RuntimeMinutes” />

        </div>

        <div>

            <input type=”submit” value=”Save” />

        </div>

    </div>

</form> 

Finally, a MovieController class with two actions is created:

using Microsoft.AspNetCore.Mvc;

using ModelStateCoreDemo.ViewModels;

public class MovieController : Controller

{

    [HttpGet(“movies/add”)]

    public IActionResult Add()

    {

        AddMovieVM model = new AddMovieVM();

        return View(model);

    }

    [HttpPost(“movies/add/post”)]

    public IActionResult AddPost(AddMovieVM model)

    {

        if(!ModelState.IsValid)

        {

            return View(“Add”, model);

        }

        return RedirectToAction(“Index”);

    }

}

36. How do you implement a microservices architecture with the ASP.NET Core Web API?

A monolithic program can be divided into smaller, autonomous services that communicate across a network to create and implement microservices. 

Implement service discovery and communication protocols like REST or gRPC, and use technologies like Docker for containerization.

You can use the ASP.NET Core Web API to construct a microservices architecture in the following ways:

• Create a project: Create a new project using Visual Studio 2022 and choose the ASP.NET Core Web API template.
• Use an API gateway: To unite microservices and route requests to the relevant microservice, use an open-source API gateway such as Ocelot.
• Design for scalability: To develop scalable applications, adhere to the concepts of dependency inversion and separation of concerns.
• Employ a database per microservice: To guarantee that every service is separate and autonomous, use a database per microservice.
• Implement security measures: Put security measures in place to safeguard your application.
• Deploy CI/CD pipeline: Put your application’s CI/CD pipeline into action. 

37. Describe Domain-Driven Design (DDD) using an ASP.NET Core Web API application as an example.

DDD entails comprehending the issue domain, modeling domain entities, aggregates, value objects, and domain services, as well as creating a common language between developers and domain experts.

Layers in a DDD Microservice Project

In medium-sized and big applications with substantial business model complexity, layering is frequently utilized. Developers can better handle this complexity by organizing software into layers, which makes maintenance, evolution, and responsibility separation easier. Among the most often utilized layers are: 

• Domain layer: Regardless of technology specifics, this layer contains the fundamental business logic and domain rules.
• Application Layer: Without including business logic, the application layer orchestrates and coordinates interactions between the presentation and domain layers.
• Infrastructure Layer: Technical elements like data durability, connectivity with other services, and external integrations are implemented via the infrastructure layer.

By modularizing the application, this method increases its scalability and resilience. 

Conclusion

It requires a combination of theoretical knowledge and hands-on coding skills to prepare for an ASP.NET interview. You’ll be prepared to confidently answer a variety of ASP.NET interview questions if you can grasp these concepts. Good luck with your preparation! If you need any further assistance or practice, enroll in our ASP.NET training in Chennai.