Posts tagged .Net interview questions

Asp.net / webservice Interview questions

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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?
False

3. What does WSDL stand for?
Web Services Description Language.

4. Where on the Internet would you look for Web services?
http://www.uddi.org

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…
________________________________________
255

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
and provides
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

Answer: B
What is the default authentication mode for IIS
Ans:
A) Windows
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

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.

Hi All,
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
20

Whats the use of @ Register directives ?
@ Register
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” %>
Attributes
tagprefix
An alias to associate with a namespace.
tagname
An alias to associate with a class.
Namespace
The namespace to associate with tagprefix.
Src
The location (relative or absolute) of the declarative User Control file to associate with the tagprefix:tagname pair.
Assembly
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,
Danasegarane Arunachalam

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.NET Framework Interview questions

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What is the Microsoft.NET?
.NET is a set of technologies designed to transform the internet into a full scale distributed platform. It provides new ways of connecting systems, information and devices through a collection of web services. It also provides a language independent, consistent programming model across all tiers of an application.
The goal of the .NET platform is to simplify web development by providing all of the tools and technologies that one needs to build distributed web applications.
What is the .NET Framework?
The .NET Framework is set of technologies that form an integral part of the .NET Platform. It is Microsoft’s managed code programming model for building applications that have visually stunning user experiences, seamless and secure communication, and the ability to model a range of business processes.
The .NET Framework has two main components: the common language runtime (CLR) and .NET Framework class library. The CLR is the foundation of the .NET framework and provides a common set of services for projects that act as building blocks to build up applications across all tiers. It simplifies development and provides a robust and simplified environment which provides common services to build application. The .NET framework class library is a collection of reusable types and exposes features of the runtime. It contains of a set of classes that is used to access common functionality.
What is CLR?
The .NET Framework provides a runtime environment called the Common Language Runtime or CLR. The CLR can be compared to the Java Virtual Machine or JVM in Java. CLR handles the execution of code and provides useful services for the implementation of the program. In addition to executing code, CLR provides services such as memory management, thread management, security management, code verification, compilation, and other system services. It enforces rules that in turn provide a robust and secure execution environment for .NET applications.
What is CTS?
Common Type System (CTS) describes the datatypes that can be used by managed code. CTS defines how these types are declared, used and managed in the runtime. It facilitates cross-language integration, type safety, and high performance code execution. The rules defined in CTS can be used to define your own classes and values.
What is CLS?
Common Language Specification (CLS) defines the rules and standards to which languages must adhere to in order to be compatible with other .NET languages. This enables C# developers to inherit from classes defined in VB.NET or other .NET compatible languages.
What is managed code?
The .NET Framework provides a run-time environment called the Common Language Runtime, which manages the execution of code and provides services that make the development process easier. Compilers and tools expose the runtime’s functionality and enable you to write code that benefits from this managed execution environment. The code that runs within the common language runtime is called managed code.
What is MSIL?
When the code is compiled, the compiler translates your code into Microsoft intermediate language (MSIL). The common language runtime includes a JIT compiler for converting this MSIL then to native code.
MSIL contains metadata that is the key to cross language interoperability. Since this metadata is standardized across all .NET languages, a program written in one language can understand the metadata and execute code, written in a different language. MSIL includes instructions for loading, storing, initializing, and calling methods on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operations.
What is JIT?
JIT is a compiler that converts MSIL to native code. The native code consists of hardware specific instructions that can be executed by the CPU.
Rather than converting the entire MSIL (in a portable executable[PE]file) to native code, the JIT converts the MSIL as it is needed during execution. This converted native code is stored so that it is accessible for subsequent calls.
What is portable executable (PE)?
PE is the file format defining the structure that all executable files (EXE) and Dynamic Link Libraries (DLL) must use to allow them to be loaded and executed by Windows. PE is derived from the Microsoft Common Object File Format (COFF). The EXE and DLL files created using the .NET Framework obey the PE/COFF formats and also add additional header and data sections to the files that are only used by the CLR.
What is an application domain?
Application domain is the boundary within which an application runs. A process can contain multiple application domains. Application domains provide an isolated environment to applications that is similar to the isolation provided by processes. An application running inside one application domain cannot directly access the code running inside another application domain. To access the code running in another application domain, an application needs to use a proxy.
How does an AppDomain get created?
AppDomains are usually created by hosts. Examples of hosts are the Windows Shell, ASP.NET and IE. When you run a .NET application from the command-line, the host is the Shell. The Shell creates a new AppDomain for every application. AppDomains can also be explicitly created by .NET applications.
What is an assembly?
An assembly is a collection of one or more .exe or dll’s. An assembly is the fundamental unit for application development and deployment in the .NET Framework. An assembly contains a collection of types and resources that are built to work together and form a logical unit of functionality. An assembly provides the CLR with the information it needs to be aware of type implementations.
What are the contents of assembly?
A static assembly can consist of four elements:
· Assembly manifest – Contains the assembly metadata. An assembly manifest contains the information about the identity and version of the assembly. It also contains the information required to resolve references to types and resources.
· Type metadata – Binary information that describes a program.
· Microsoft intermediate language (MSIL) code.
· A set of resources.
What are the different types of assembly?
Assemblies can also be private or shared. A private assembly is installed in the installation directory of an application and is accessible to that application only. On the other hand, a shared assembly is shared by multiple applications. A shared assembly has a strong name and is installed in the GAC.
We also have satellite assemblies that are often used to deploy language-specific resources for an application.
What is a dynamic assembly?
A dynamic assembly is created dynamically at run time when an application requires the types within these assemblies.
What is a strong name?
You need to assign a strong name to an assembly to place it in the GAC and make it globally accessible. A strong name consists of a name that consists of an assembly’s identity (text name, version number, and culture information), a public key and a digital signature generated over the assembly. The .NET Framework provides a tool called the Strong Name Tool (Sn.exe), which allows verification and key pair and signature generation.
What is GAC? What are the steps to create an assembly and add it to the GAC?
The global assembly cache (GAC) is a machine-wide code cache that stores assemblies specifically designated to be shared by several applications on the computer. You should share assemblies by installing them into the global assembly cache only when you need to.
Steps
– Create a strong name using sn.exe tool eg: sn -k mykey.snk
– in AssemblyInfo.cs, add the strong name eg: [assembly: AssemblyKeyFile(“mykey.snk”)]
– recompile project, and then install it to GAC in two ways :
· drag & drop it to assembly folder (C:\WINDOWS\assembly OR C:\WINNT\assembly) (shfusion.dll tool)
· gacutil -i abc.dll
What is the caspol.exe tool used for?
The caspol tool grants and modifies permissions to code groups at the user policy, machine policy, and enterprise policy levels.
What is a garbage collector?
A garbage collector performs periodic checks on the managed heap to identify objects that are no longer required by the program and removes them from memory.
What are generations and how are they used by the garbage collector?
Generations are the division of objects on the managed heap used by the garbage collector. This mechanism allows the garbage collector to perform highly optimized garbage collection. The unreachable objects are placed in generation 0, the reachable objects are placed in generation 1, and the objects that survive the collection process are promoted to higher generations.
What is Ilasm.exe used for?
Ilasm.exe is a tool that generates PE files from MSIL code. You can run the resulting executable to determine whether the MSIL code performs as expected.
What is Ildasm.exe used for?
Ildasm.exe is a tool that takes a PE file containing the MSIL code as a parameter and creates a text file that contains managed code.
What is the ResGen.exe tool used for?
ResGen.exe is a tool that is used to convert resource files in the form of .txt or .resx files to common language runtime binary .resources files that can be compiled into satellite assemblies.

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