You are an ASP.NET programmer… Your next job interview is round the corner… You want to score that job… All that means is that you need to prepare well despite being knowledgeable in the domain. Generally, in technical job interviews, interviewers will not only ask complex questions, but you may also even face some very fundamental and rudimentary questions which can make or break the chance to win.
You may need more than this set of questions to arm yourself fully for the interview. We recommend you to visit ASP .NET Tutorials and Courses, where you can find more reading material and get a full grip of ASP.NET.
Answer: ASP.NET is an open-source server-side application framework designed for web developers to produce dynamic web pages with .NET framework. It was developed by Microsoft to allow programmers to build dynamic web sites, web applications and web services.
Answer: ASP.NET MVC is a web application framework for the .NET Platform used for building full stack web applications using the Model-View-Controller pattern.
Answer: ASP.NET Web API is used purely for building backend web APIs which can be used by an array of clients, from the web to desktop to mobile. It forms the server component in the RESTful (Representational State Transfer) architecture.
Answer: If one intends to build a server component that can be easily utilized by an array of clients then ASP.NET Web API is the way to go. If, however, the project is purely going to be used as a web application, then ASP.NET MVC is a more appropriate choice.
Answer: The web.config file is crucial because it contains the configuration settings for the application. It keeps your entire configuration separate from your code so you can easily change settings without code changes. It also allows you to potentially encrypt the configuration settings for increased security.
Answer: Roslyn is the name of the compiler used by .NET Framework.
Answer: Microsoft is providing the full .NET server stack in open source which means it is a ‘free’ download. This includes ASP.NET, the .NET compiler, the .NET Core Runtime, Framework, and Libraries, enabling developers to build with .NET across Windows, Mac or Linux.
Answer: Request flow handles the request from the clients and passes it to the server. Request hits the controller coming from the client. Controller plays its role and decides which model to use in order to serve the request further, passing that model to view which then transforms the model and generates an appropriate response that is rendered to the client.
Answer: There are various modes for storing session state:
Answer:
| GridView | DataGrid |
| In-built support for paging, sorting and in-place editing using PagerSettings property. | Requires custom code for paging, sorting and editing. |
| Uses data source control's sorting, update, delete, and paging options. | Only data selection is supported by default. Updates and deletions need custom code. |
| Supports additional column types like HyperLinkField, ButtonField etc. | Supports only limited column types. |
| Supports both preoperative and postoperative events. | Raises single events for operations. |
Answer:
| Repeater | ListView |
| Flexible layout introduced in .NET 1.0. | Flexible layout with easy customization introduced with .NET 3.5 |
| No built-in support, custom code should be written for data grouping and paging. | Provides built-in support for data grouping and paging. |
| Update, insert, delete and sorting operations are not supported. | All the operations are supported. |
| Offers better performance. | Slower performance compared to a repeater. |
Answer:
| Local Resources | Global Resources |
| A local resource can only be accessed by the page that created it. | Accessible by all pages. |
| Difficult to maintain when the website has a lot of localized content as each page requires a resource file for each language. | Only one file per language is required. |
| Stored in the App_LocalResources folder. | Stored in the App_GlobalResources folder. |
Answer: Globalization is the growth of business outside the national borders. It involves understanding the laws and regulations of various countries to build the business environment. Globalization includes internalization and localization.
Localization is a procedure where a product is made available for the local market by making it appealing for the local community. It includes local preferences, culture and regional aspects other than just the translation of web pages in the local language.
For a stable worldwide business, you need both globalization – through which you can increase the reach of your business and localization – where you can show customized content based on the local preferences and other aspects.
These help in effective target marketing and cohesive global strategy.
Answer:
| User Control | Custom Control |
| Stored as .ascx extension. | It is a .dll extension. |
| They have a visual interface. | These controls don't have a visual interface. |
| Do not appear in the toolbox and does not have design support; loaded at runtime. | Can be added to the toolbox and used in various applications without re-compilation. |
| If we need controls particular to a website, user control is a good option. | Custom controls can be created to be used across various applications. |
Answer: Server controls are the primary controls in ASP.NET and are categorized in the following groups:
Question: Explain various page events in ASP.NET?
Answer: The various page events in ASP.NET are:
| Event | Description |
| Page request | This event happens before the lifecycle begins. Whenever a user requests a page, ASP.NET parses and compiles the page. |
| Start | Properties like Request and response are set, and the Request type is determined through this event |
| Initialize | This event sets each control's UniqueID property and applies the Master page to the page. |
| Rendering | In this event, 'Render' method is called for each control. A text writer writes the output (view state) to OutputStream object of the page's Response property |
| Load | control properties are loaded with information if page request is a postback, |
| Postback event handling | If page request is a postback, an event handler is called through this event. Afterwards, the Validate method of all validator controls is called |
| Unload | This event happens after the requested page is fully rendered and is ready to discontinue. All properties are unloaded, and cleanup is done. |
Answer: Connection string contains information about the data source and how to connect to it.
Connection string is added as follows:
Answer:
| web.config | machine.config |
| Stores the configuration settings for a particular web application. | Specifies the configuration settings for all the websites hosted on the web server. |
| Located in the application's root directory. | Located in $WINDOWSDIR$\Microsoft.Net\Framework\Version\Config |
| Overrides the settings in machine.config file. | It is a master file that provides default settings that can be overridden. |
Answer: It is an optional file and is also called as the application file for ASP.NET. It contains code that responds to session-level and application-level events raised by HTTP modules or ASP.NET.
Answer:
| Website | Web Application |
| Contains static content available publicly to all the visitors. | Dynamic and interactive content. |
| The content is readable by all but cannot be changed or manipulated. | An end-user can read and manipulate the restricted data. |
| These are mostly informational websites hence authentication is not mandatory. | Needs authentication as these have more features and options for the user. |
| It is simple to create as just information is loaded and updated. | Since there is interaction with the end-user, web applications are complex and perform more functions. |
| Website is a whole product that is accessible through the browser. | It is one part of the whole website. it cannot be accessed directly. |
| No pre-compilation is required, only HTML code needs to be refreshed. | Pre-compilation is required before deployment. |
Question: Explain View State? And its advantages and disadvantages.
Answer: Suppose a user submits a form and there are validation errors or if the page refreshes after the user enters a lot of information on the page. In such cases, the information already written by the user will be lost, and he/she has to fill everything again. To avoid this from happening, ASP.NET uses ViewState, which retains the values already entered by the user. It is a built-in state management technique to preserve the form data.
Advantages:
Disadvantages:
Answer: A cookie is a part of text that stores user-specific data. Cookies are stored by the browser in a user's hard drive and used whenever the user requests for a particular page. Cookies help in improving user experience and loading pages faster based on the date and time information stored as part of the data. In ASP, cookies can be created as well as retrieved. There are two types of cookies in ASP – persist, non-persist.
Answer: ASP.NET can create web services which are nothing but programs that use XML to exchange data with other software programs through commonly used internet protocols. We can communicate with any object over the internet using web service.
Web services are language-independent, platform-independent, protocol-independent, self-describing and programmable.
Answer: App domain or application domain in ASP.NET is a light-weight process that has its own set of code, configuration and data settings. It is a logical boundary that separates one application from accessing or interfering with others. App domains help in better utilization of resources by using fewer processes for executing different applications. For example, ASP.NET is a runtime host that creates different application domains for every user who accesses a web site. These can be created and set up for apps that need to isolate code or to load extensions dynamically.
Answer: A query string is a method of transporting data from page to page using the browser URL. It is attached to the URL using the question mark symbol (?). For example, http://xyz.com?userid=12334&pwd=rf5r5jm3smQ
Advantages: Easy to use, no server resources required, supported by all the browsers, contained in the HTTP request of the URL
Disadvantages: URL length cannot be greater than 255 characters; data is directly visible to everyone compromising the security.
Answer: Tracing in .net enables one to follow the execution path of a page, debug the application and display diagnostic information at runtime. Trace messages can be accessed and manipulated from the code allowing for finer control to add more details. The tracing data is organized into a set of tables by ASP.NET.
Answer: The checkbox is used to get multiple inputs from the user. Users can select more than one choice from the given options. In the code, it is set as a yes/no or true/false option, when it is ticked, the value of the checkbox is true, else false.
Answer: HTML server controls provide automatic state and server-side event management. These are HTML elements that have the attribute runat=server. The HTML server control properties and output are the same as their equivalent HTML tags. These controls are compiled when the ASP.NET application is compiled.
Answer: HTTP is stateless, i.e. doesn't remember the state of a user, for example, his previously visited websites, requests and URLs. However, for certain requests, we need to maintain the state of application until the end, and ASP.NET has two approaches for the same:
Answer: Login control provides a secure login solution with a user interface and properties for the customized display of text fields, messages and links for forgotten password and to other pages.
We can modify the existing LoginControl and select the format. Login control properties can be written in HTML as follows:
These can be set in CSS file too:
.LoginControl
<
background-color:#FFFFFF;
border-color:#CDCC99;
border-style:solid;
border-width:1px;
font-family:Times New Roman;
font-size:10px;
>
We can apply the CSS to the control using the CssClass attribute:
Answer: A PostBack happens when a user takes some action (like submitting a form) that sends information from the page to the server for processing via POST method.
Answer: ASP.NET goes through a series of stages in the life cycle of each page.
Answer: View state is where data is used to preserve page values and control values of Web Forms during postback event handling. Data can be stored as hidden fields on the client web page.
Answer: Custom controls are basically compiled code, i.e., DLLs. These can be easily added to the toolbox, so it can be easily used across multiple projects using a drag-and-drop approach. These controls are comparatively hard to create. But User Controls (.ascx) are just like pages (.aspx). These are comparatively easy to create but tightly coupled with respect to User Interface and code.
Answer: ASP.NET validation controls define an important role in validating the user input data. Whenever the user gives input, it must always be validated before sending it across the various layers of an application. There are two types of validation in ASP.NET:
Client-Side Validation: When validation is done on the client browser, it is known as Client-Side Validation. You can use JavaScript to do the Client-Side Validation.
Server-Side Validation: When validation occurs on the server, then it is known as Server-Side Validation. Server-Side Validation is a secure form of validation. The main advantage of Server-Side Validation is if the user bypasses the Client-Side Validation, the problem can be caught on the server-side.
The following are the Validation Controls in ASP.NET:
Answer: The Finalize method is used to perform cleanup operations on unmanaged resources held by an object. It puts an object in the finalization queue. The Object will then be collected by the garbage collector ready to be cleaned up.
Answer: RedirectPermanent Performs a permanent redirection from the requested URL to the specified URL. Once the redirection is done, it also returns http 301 status code to the browser.
Answer: LoginStatus control is used to display Login/Logout links based on the login/authorization status of the current user. If the user has successfully logged in, the Logout link will be displayed.
Answer: A Repeater is a Data-bound control. Data-bound controls are container controls. It creates a link between the Data Source and the presentation UI to display the data. The repeater control is used to display a repeated list of items. A Repeater has five inline templates to format it:
Answer: In-Process and Out-of-Process are the two session state management options.
Answer: Server. Transfer sends information from one web request to another, all on the server side. A response is not sent to the browser. On the other hand, Response.Redirect sends an HTTP 302 message to the browser and causes a redirect in the browser.
Answer: Fragment caching refers to the caching of individual user controls within a Web Form. Each user control can have independent cache durations and implementations of how the caching behavior is to be applied. Fragment caching is useful when you need to cache only a subset of a page.
Answer: Web controls are classes in the .NET framework. The controls have special tags understood by the server. They are created on the server and require a run at=”server” attribute to execute. They generate HTML code that is sent back to the browser.
Answer:
Answer: A Web service, in the context of .NET, is a component that resides on a Web server and provides information and services to other network applications using standard Web protocols such as HTTP and Simple Object Access Protocol (SOAP).
Answer: The difference between session and application object is that all users share one Application object and with sessions, there is one session object for each user. Data stored in the application object can be shared by all the sessions of the application. Application object stores data in the key-value pair. Session object stores session-specific information and the information are visible within the session only. ASP.NET creates unique SessionId for each session of the application. SessionIDs are maintained either by an HTTP cookie or a modified URL, as set in the applications configuration settings. By default, SessionID values are stored in cookies.
Answer: Caching is a mechanism that improves performance for an application by storing data in the memory for faster access. When the application accesses data from Cache (i.e. in-memory) instead of fetching it from the original data store (maybe a database), it definitely improves performance. But Caching benefits are not limited only to performance; it also improves application Scalability and Availability.
Answer: There are three types of authentication available in ASP.NET:
Answer: Microsoft has provided an implementation of AJAX functionality known as ASP.NET AJAX. AJAX stands for Asynchronous JavaScript and XML. This is a cross-platform technology that speeds up response time and reduces traffic between client and server. ASP.NET AJAX is a set of extensions to ASP.NET and comes with reusable AJAX controls.
Answer: REST (Representational State Transfer) is an architectural style for designing applications and it dictates to use HTTP for making calls for communications instead of complex mechanism like CORBA, RPC or SOAP. There are few principles associated with REST architectural style:
Answer: ASP.NET applications can be developed and run on any operating systems like Windows, Linux, macOS, and Docker. Hence it is called a Cross-platform framework.
Answer: Razor is a markup syntax that lets you embed server-based code (Visual Basic and C#) into web pages. The server-based code can create dynamic web content on the fly, while a web page is written to the browser. When a web page is called, the server executes the server-based code inside the page before it returns the page to the browser. By running on the server, the code can perform complex tasks, like accessing databases. Razor is based on ASP.NET, and designed for creating web applications. It has the power of traditional ASP.NET markup, but it is easier to use and easier to learn.
Answer: ASP.NET Core is the open-source and cross-platform version of ASP.NET. The Windows-only versions of ASP.NET, that existed before ASP.NET Core, is typically just referred to as ASP.NET.
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