.net interview questions
ASP.NET Interview Questions
This is a list of questions I have gathered and created over a period of time from my experience, many of which I felt where incomplete or simply wrong. I have finally taken the time to go through each question and correct them to the best of my ability. However, please feel free to post feedback to challenge, improve, or suggest new questions. I want to thank those of you that have contributed quality questions and corrections thus far.
There are some questions in this list that I do not consider to be good questions for an interview. However, they do exist on other lists available on the Internet so I felt compelled to keep them here for easy access.
1. Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading process.
inetinfo.exe is theMicrosoft IIS server running, handling ASP.NET requests among other things.When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request tothe actual worker process aspnet_wp.exe.
2. What’s the difference between Response.Write() andResponse.Output.Write()?
Response.Output.Write() allows you to write formatted output.
3. What methods are fired during the page load?
Init() – when the page is instantiated
Load() – when the page is loaded into server memory
PreRender() – the brief moment before the page is displayed to the user as HTML
Unload() – when page finishes loading.
4. When during the page processing cycle is ViewState available?
After the Init() and before the Page_Load(), or OnLoad() for a control.
5. What namespace does the Web page belong in the .NET Framework class hierarchy?
6. Where do you store the information about the user’s locale?
7. What’s the difference between Codebehind=”MyCode.aspx.cs” andSrc=”MyCode.aspx.cs”?
CodeBehind is relevant to Visual Studio.NET only.
8. What’s a bubbled event?
When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.
9. Suppose you want a certain ASP.NET function executed on MouseOver for a certain button. Where do you add an event handler?
Add an OnMouseOver attribute to the button. Example: btnSubmit.Attributes.Add(“onmouseover”,”someClientCodeHere();”);
10. What data types do the RangeValidator control support?
Integer, String, and Date.
11. Explain the differences between Server-side and Client-side code?
Server-side code executes on the server. Client-side code executes in the client’s browser.
12. What type of code (server or client) is found in a Code-Behind class?
13. Should user input data validation occur server-side or client-side? Why?
All user input data validation should occur on the server at a minimum. Additionally, client-side validation can be performed where deemed appropriate and feasable to provide a richer, more responsive experience for the user.
14. What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?
Server.Transfer transfers page processing from one page directly to the next page without making a round-trip back to the client’s browser. This provides a faster response with a little less overhead on the server. Server.Transfer does not update the clients url history list or current url. Response.Redirect is used to redirect the user’s browser to another page or site. This performas a trip back to the client where the client’s browser is redirected to the new page. The user’s browser history list is updated to reflect the new address.
15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?
Valid answers are:
• A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.
• A DataSet is designed to work without any continuing connection to the original data source.
• Data in a DataSet is bulk-loaded, rather than being loaded on demand.
• There’s no concept of cursor types in a DataSet.
• DataSets have no current record pointer You can use For Each loops to move through the data.
• You can store many edits in a DataSet, and write them to the original data source in a single operation.
• Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.
16. What is the Global.asax used for?
The Global.asax (including the Global.asax.cs file) is used to implement application and session level events.
17. What are the Application_Start and Session_Start subroutines used for?
This is where you can set the specific variables for the Application and Session objects.
18. Can you explain what inheritance is and an example of when you might use it?
When you want to inherit (use the functionality of) another class. Example: With a base class named Employee, a Manager class could be derived from the Employee base class.
19. Whats an assembly?
Assemblies are the building blocks of the .NET framework. Overview of assemblies from MSDN
20. Describe the difference between inline and code behind.
Inline code written along side the html in a page. Code-behind is code written in a separate file and referenced by the .aspx page.
21. Explain what a diffgram is, and a good use for one?
The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. A good use is reading database data to an XML file to be sent to a Web Service.
22. Whats MSIL, and why should my developers need an appreciation of it if at all?
MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get converted to MSIL. MSIL also allows the .NET Framework to JIT compile the assembly on the installed computer.
23. Which method do you invoke on the DataAdapter control to load your generated dataset with data?
The Fill() method.
24. Can you edit data in the Repeater control?
No, it just reads the information from its data source.
25. Which template must you provide, in order to display data in a Repeater control?
26. How can you provide an alternating color scheme in a Repeater control?
Use the AlternatingItemTemplate.
27. What property must you set, and what method must you call in your code, in order to bind the data from a data source to the Repeater control?
You must set the DataSource property and call the DataBind method.
28. What base class do all Web Forms inherit from?
The Page class.
29. Name two properties common in every validation control?
ControlToValidate property and Text property.
30. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
31. Which control would you use if you needed to make sure the values in two different controls matched?
32. How many classes can a single .NET DLL contain?
It can contain many classes.
Web Service Questions
1. What is the transport protocol you use to call a Web service?
SOAP (Simple Object Access Protocol) is the preferred protocol.
2. True or False: A Web service can only be written in .NET?
3. What does WSDL stand for?
Web Services Description Language.
4. Where on the Internet would you look for Web services?
5. True or False: To test a Web service you must create a Windows application or Web application to consume this service?
False, the web service comes with a test page and it provides HTTP-GET method to test.
State Management Questions
1. What is ViewState?
ViewState allows the state of objects (serializable) to be stored in a hidden field on the page. ViewState is transported to the client and back to the server, and is not stored on the server or any other external source. ViewState is used the retain the state of server-side objects between postabacks.
2. What is the lifespan for items stored in ViewState?
Item stored in ViewState exist for the life of the current page. This includes postbacks (to the same page).
3. What does the “EnableViewState” property do? Why would I want it on or off?
It allows the page to save the users input on a form across postbacks. It saves the server-side values for a given control into ViewState, which is stored as a hidden value on the page before sending the page to the clients browser. When the page is posted back to the server the server control is recreated with the state stored in viewstate.
4. What are the different types of Session state management options available with ASP.NET?
ASP.NET provides In-Process and Out-of-Process state management. In-Process stores the session in memory on the web server. This requires the a “sticky-server” (or no load-balancing) so that the user is always reconnected to the same web server. Out-of-Process Session state management stores data in an external data source. The external data source may be either a SQL Server or a State Server service. Out-of-Process state management requires that all objects stored in session are serializable.
is there any limit for query string? if means what…
How to create a package for web application with components that shared with other applications?
Create a setup project which produces a .msi file.
A shared component assembly must be given a strong name using the following steps:
1. Create a key pair using sn.exe -k on the command line
2. Add AssemblyKeyFileAttribute to the assembly file and set it to the full name and path of the key file generated in step 1.
3. Build the assembly
The setup program detects a strong named assembly and installs it into GAC on the client machine.
what is .net frame work?
.Net framework is an environment provided on top of the OS which looks into
1. Memory management
2. Thread management
1. Language independence
2. Platform independence
It is defined by Microsoft as ‘an environment for building, deploying and running web services and other applications. It consists of three main parts — CLR, framework classes and ASP.Net’
.Net facilitates integration of code written for desktop applications with code written for web applications. It also facilitates creation of assemblies from code files written in different .net languages. It provides a common type system (CTS) for bringing data types of all languages on a common platform.
What do you mean by authentication and authorization
Simple answer to this is as follows Authentication is process of finding whether the user is valid.Example username and password u enter in mail page.That process is authentication Authorization is the process of holding rights for particular task.Example: Usually admin have right to install software in companies and others are not granted this right.
What is difference between Authentication and Authorization?
Authentication–>Checking the validity.Ex:A creditcard validation by Verisign.It is called authenticating the CreditCard
Authorization–>Giving some rights -Ex:I authorize mr.Rahul to sign some papers realted with my bank accounts
You are logged on to a client. You do not have a secure connection from your client to the host
where your Oracle database is running. Which authentication mechanism allows you to connect to the database
using the SYSDBA privilege?
A. Control file authentication
B. Password file authentication
C. Data dictionary authentication
D. Operating system authentication
What is the default authentication mode for IIS
Explain Assemblies?,Difference between Panel and GroupBox?,Differences between ASP and ASP.NET
Assemblies are single deployable unit which consist of classes structures and interface.they consist of metadata which desrcibes assembly version ,name ,type etc. They are known as logical DLL’s .
panel are scrollable and in panels captions can not be displayed.
it is vice versa incase of group box
Asp is not compiled that is interperated where as ASP.net is compiled.
Assemblies are the building blocks of .NET Framework applications; they form the fundamental unit of deployment, version control, reuse, activation scoping, and security permissions. An assembly is a collection of types and resources that are built to work together and form a logical unit of functionality. An assembly provides the common language runtime with the information it needs to be aware of type implementations. To the runtime, a type does not exist outside the context of an assembly.
I found that there are numerous posts for Assemblies but none for giving out the difference between Panel and a Group Box. Although a Panel as well as the groupbox are almost the same there are minute differences.
In group box you can enter text while you cant do that in Panel.
In Panel you have got a built in support for scrollbars which is not available in case of group box.
What is the difference between excute query and excute nonquery.?
Execute Query is the method which is used to return the result of the command like select Query. That is Update Query. The Execute Non Query
is used to return the Query os the statement like the update Delete Insert which returns No data
What is the Subquery ?
Sub query is a query whose return values are used in filtering conditions of the main query.
What is the maximum number of cookies that can be allowed to a web site
Whats the use of @ Register directives ?
Associates aliases with namespaces and class names for concise notation in custom server control syntax.
<%@ Register tagprefix=”tagprefix” Namespace=”namespace” Assembly=”assembly” %><%@ Register tagprefix=”tagprefix” Tagname=”tagname” Src=”pathname” %>
An alias to associate with a namespace.
An alias to associate with a class.
The namespace to associate with tagprefix.
The location (relative or absolute) of the declarative User Control file to associate with the tagprefix:tagname pair.
The assembly in which the namespace that you are associating with tagprefix resides.
Note The assembly name does not include a file name extension.
In DataGrid, is it possible to add rows one by one at runtime. That means after entering data in one row next row will be added.
Yes, for this you have to use datatable and after inserting the first row in datatable u have to bind that datatable to the grid and next time , first u have to add the row in datatable and next bind it to datagrid. keep on doing.
u have to maintain the datatable state
Thanks & Regards,
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