Adblock Detected

Read

ASP.NET Fundamentals: 7 Pillars of ASP.NET: A Basic Interview Question

Read

ASP.NET Fundamentals: 7 Pillars of ASP.NET: A Basic Interview Question

If you are preparing for ASP.NET interview, must be ready for basic ASP.NET interview question "What are the Pillars of ASP.NET?" Pillars of ASP.NET means the fundamentals of ASP.NET like .NET Framework, CLS, CTS, MSIL, JIT, Object Oriented Concepts, Assemblies, DLLs, XCopy Deployment etc. I have listed down 7 Pillars of ASP.NET in detail.

7 Pillars of ASP.NET:

When ASP.NET was first released, there were seven key facts that differentiated it from previous Microsoft products and competing platforms. If you’re coming to ASP.NET from another web development platform, or you’re an old-hand .NET coder who has yet to try programming for the Web, these sections will quickly give you a bit of ASP.NET insight.

1: ASP.NET is integrated with the .NET Framework

2: ASP.NET is Compiled, Not Interpreted

ASP.NET applications, like all .NET applications, are always compiled. In fact, it’s impossible to execute C# or Visual Basic code without it being compiled first.

3: ASP.NET is Multilanguage

No matter what language you use, the code is compiled into MSIL. MSIL is a stepping stone for every managed application.

4: ASP.NET is Hosted by the Common Language Runtime

Perhaps the most important aspect of the ASP.NET engine is that it runs inside the runtime environment of the CLR. The whole of the .NET Framework—that is, all namespaces, applications, and classes—is referred to as managed code. Basic features of CLR are:

A) Automatic memory management and garbage collection

B) Type safety

C) Extensible metadata

D) Structured error handling

E) Multithreading

5: ASP.NET is Object-Oriented

ASP.NET is truly object oriented. Not only does your code have full access to all objects in the .NET Framework, but you can also exploit all the conventions of an OOP (object-oriented programming) environment.

6: ASP.NET supports all Browsers

ASP.NET addresses the problem of cross browser compatibility in a remarkably intelligent way. Although you can retrieve information about the client browser and its capabilities in an ASP.NET page, ASP.NET actually encourages developers to ignore these considerations and use a rich suite of web server controls. These server controls render their markup adaptively by taking the client’s capabilities into account.

7: ASP.NET is Easy to Deploy and Configure

ASP.NET Fundamentals: ASP.NET is integrated with the .NET Framework

Read

ASP.NET Fundamentals: ASP.NET is integrated with the .NET Framework

The .NET Framework is divided into an almost painstaking collection of functional parts, with tens of thousands of types (the .NET term for classes, structures, interfaces, and other core programming ingredients). Before you can program any sort of .NET application, you need a basic understanding of those parts—and an understanding of why things are organized the way they are. The massive collection of functionality that the .NET Framework provides is organized in a way that traditional Windows programmers will see as a happy improvement. Each one of the thousands of classes in the .NET Framework is grouped into a logical, hierarchical container called a namespace. Different namespaces provide different features. Taken together, the .NET namespaces offer functionality for nearly every aspect of distributed development from message queuing to security. This massive toolkit is called the class library.

Interestingly, the way you use the .NET Framework classes in ASP.NET is the same as the way you use them in any other type of .NET application (including a stand-alone Windows application, a Windows service, a command-line utility, and so on). Although there are Windows-specific and web-specific classes for building user interfaces, the vast majority of the .NET Framework (including everything from database access to multithreaded programming) is usable in any type of application. In other words, .NET gives the same tools to web developers that it gives to rich client developers.

Tip: One of the best resources for learning about new corners of the .NET Framework is the .NET Framework class library reference, which is part of the MSDN Help library reference. If you have Visual Studio 2012 installed, you can view the MSDN Help library by clicking the Start button and choosing Programs ➤ Microsoft Visual Studio 2012 ➤ Microsoft Visual Studio 2012 Documentation (the exact shortcut depends on your version of Visual Studio).

ASP.NET Fundamentals: ASP.NET supports all Browsers

Read

ASP.NET Fundamentals: ASP.NET is Easy to Deploy and Configure

Read

ASP.NET Fundamentals: ASP.NET is Easy to Deploy and Configure

One of the biggest headaches a web developer faces during a development cycle is deploying a completed application to a production server. Not only do the web-page files, databases, and components need to be transferred, but components need to be registered and a slew of configuration settings need to be re-created. ASP.NET simplifies this process considerably.

Every installation of the .NET Framework provides the same core classes. As a result, deploying an ASP.NET application is relatively simple. For no-frills deployment, you simply need to copy all the files to a virtual directory on a production server (using an FTP program or even a command-line command like XCOPY). As long as the host machine has the .NET Framework, there are no time-consuming registration steps. Chapter 18 covers deployment in detail.

Distributing the components your application uses is just as easy. All you need to do is copy the component assemblies along with your website files when you deploy your web application. Because all the information about your component is stored directly in the assembly file metadata, there’s no need to launch a registration program or modify the Windows registry. As long as you place these components in the correct place (the Bin subdirectory of the web application directory), the ASP.NET engine automatically detects them and makes them available to your web-page code. Try that with a traditional COM component!

Configuration is another challenge with application deployment, particularly if you need to transfer security information such as user accounts and user privileges. ASP.NET makes this deployment process easier by minimizing the dependence on settings in IIS (Internet Information Services). Instead, most ASP.NET settings are stored in a dedicated web.config file. The web.config file is placed in the same directory as your web pages. It contains a hierarchical grouping of application settings stored in an easily readable XML format that you can edit using nothing more than a text editor such as Notepad. When you modify an application setting, ASP.NET notices that change and smoothly restarts the application in a new application domain (keeping the existing application domain alive long enough to finish processing any outstanding requests). The web.config file is never locked, so it can be updated at any time.

ASP.NET Fundamentals: ASP.NET is Object-Oriented Language

Read

ASP.NET Fundamentals: ASP.NET is Object-Oriented Language

ASP provides a relatively feeble object model. It provides a small set of objects; these objects are really just a thin layer over the raw details of HTTP and HTML. On the other hand, ASP.NET is truly object oriented. Not only does your code have full access to all objects in the .NET Framework, but you can also exploit all the conventions of an OOP (object-oriented programming) environment. For example, you can create reusable classes, standardize code with interfaces, extend existing classes with inheritance, and bundle useful functionality in a distributable, compiled component.

One of the best examples of object-oriented thinking in ASP.NET is found in server-based controls. Server-based controls are the epitome of encapsulation. Developers can manipulate control objects programmatically using code to customize their appearance, provide data to display, and even react to events. The low-level HTML markup that these controls render is hidden away behind the scenes. Instead of forcing the developer to write raw HTML manually, the control objects render themselves to HTML just before the web server sends the page to the client. In this way, ASP.NET offers server controls as a way to abstract the low-level details of HTML and HTTP programming.

Here’s a quick example with a standard HTML text box that you can define in an ASP.NET web page:

With the addition of the runat="server" attribute, this static piece of HTML becomes a fully functional server-side control that you can manipulate in C# code. You can now work with events that it generates, set attributes, and bind it to a data source. For example, you can set the text of this box when the page first loads using the following C# code:

void Page_Load(object sender, EventArgs e)

{

myText.Value = "Hello World!";

}

Technically, this code sets the Value property of an HtmlInputText object. The end result is that a string of text appears in a text box on the HTML page that’s rendered and sent to the client.

HTML Controls VS. Web Controls

When ASP.NET was first created, two schools of thought existed. Some ASP.NET developers were most interested in server-side controls that matched the existing set of HTML controls exactly. This approach allows you to create ASP.NET web-page interfaces in dedicated HTML editors, and it provides a quick migration path for existing ASP pages. However, another set of ASP.NET developers saw the promise of something more—rich server-side controls that didn’t just emulate individual HTML tags. These controls might render their interface from dozens of distinct HTML elements while still providing a simple objectbased interface to the programmer. Using this model, developers could work with programmable menus, calendars, data lists, validators, and so on.

After some deliberation, Microsoft decided to provide both models. You’ve already seen an example of HTML server controls, which map directly to the basic set of HTML tags. Along with these are ASP.NET web controls, which provide a higher level of abstraction and more functionality. In most cases, you’ll use HTML server-side controls for backward compatibility and quick migration, and use web controls for new projects.

ASP.NET web control tags always start with the prefix asp: followed by the class name. For example, the following snippet creates a text box and a check box:

Again, you can interact with these controls in your code, as follows:

myASPText.Text = "New text";

myASPCheck.Text = "Check me!";

Notice that the Value property you saw with the HTML control has been replaced with a Text property. The HtmlInputText.Value property was named to match the underlying value attribute in the HTML tag. However, web controls don’t place the same emphasis on correlating with HTML syntax, so the more descriptive property name Text is used instead.

The ASP.NET family of web controls includes complex rendered controls (such as the Calendar and TreeView), along with more streamlined controls (such as TextBox, Label, and Button), which map closely to existing HTML tags. In the latter case, the HTML server-side control and the ASP.NET web control variants provide similar functionality, although the web controls tend to expose a more standardized, streamlined interface. This makes the web controls easy to learn, and it also means they’re a natural fit for Windows developers moving to the world of the Web, because many of the property names are similar to the corresponding Windows controls.

ASP.NET Fundamentals: ASP.NET is Hosted by the Common Language Runtime

Read

ASP.NET Fundamentals: ASP.NET is Hosted by the Common Language Runtime

Automatic memory management and garbage collection: Every time your application instantiates a reference-type object, the CLR allocates space on the managed heap for that object. However, you never need to clear this memory manually. As soon as your reference to an object goes out of scope (or your application ends), the object becomes available for garbage collection. The garbage collector runs periodically inside the CLR, automatically reclaiming unused memory for inaccessible objects. This model saves you from the low-level complexities of C++ memory handling and from the quirkiness of COM reference counting.

Type safety: When you compile an application, .NET adds information to your assembly that indicates details such as the available classes, their members, their data types, and so on. As a result, other applications can use them without requiring additional support files, and the compiler can verify that every call is valid at runtime. This extra layer of safety completely obliterates whole categories of low-level errors.

Extensible metadata: The information about classes and members is only one of the types of metadata that .NET stores in a compiled assembly. Metadata describes your code and allows you to provide additional information to the runtime or other services. For example, this metadata might tell a debugger how to trace your code, or it might tell Visual Studio how to display a custom control at design time. You could also use metadata to enable other runtime services, such as transactions or object pooling.

Structured error handling: .NET languages offer structured exception handling, which allows you to organize your error-handling code logically and concisely. You can create separate blocks to deal with different types of errors. You can also nest exception handlers multiple layers deep.

Multithreading: The CLR provides a pool of threads that various classes can use. For example, you can call methods, read files, or communicate with web services asynchronously, without needing to explicitly create new threads.

ASP.NET Fundamentals: ASP.NET is Multi-language

Read

ASP.NET Fundamentals: ASP.NET is Multi-language

ASP.NET is Multi-language. Though you’ll probably opt to use one language over another when you develop an application, that choice won’t determine what you can accomplish with your web applications. That’s because no matter what language you use, the code is compiled into IL.

IL is a stepping stone for every managed application. (A managed application is any application that’s written for .NET and executes inside the managed environment of the CLR.) In a sense, IL is the language of .NET, and it’s the only language that the CLR recognizes.

To understand IL, it helps to consider a simple example. Take a look at this code written in C#:

using System;

namespace HelloWorld

{

public class TestClass

{

static void Main(string[] args)

{

Console.WriteLine("Hello World");

}

This code shows the most basic application that’s possible in .NET—a simple command-line utility that displays a single, predictable message on the console window. Now look at it from a different perspective. Here’s the IL code for the Main() method:

.method private hidebysig static void Main(string[] args) cil managed

{

.entrypoint

// Code size 13 (0xd)

.maxstack 8

IL_0000: nop

IL_0001: ldstr "Hello World"

IL_0006: call void [mscorlib]System.Console::WriteLine(string)

IL_000b: nop

IL_000c: ret

} // end of method TestClass::Main

It’s easy enough to look at the IL for any compiled .NET application. You simply need to run the IL Disassembler, which is installed with Visual Studio and the .NET SDK (software development kit). Look for the file ildasm.exe in a directory like c:\Program Files\Microsoft SDKs\Windows\v7.0A\bin. Run ildasm.exe, and then use the File ➤ Open command, and select any DLL or EXE that was created with .NET.

Tip: For even more disassembling power, check out the remarkable (and free) Reflector tool at http://www.red-gate.com/products/reflector. With the help of community-created add-ins, you can use Reflector to diagram, analyze, and decompile the IL code in any assembly.

If you’re patient and a little logical, you can deconstruct the IL code fairly easily and figure out what’s happening. The fact that IL is so easy to disassemble can raise privacy and code control issues, but these issues usually aren’t of any concern to ASP.NET developers. That’s because all ASP.NET code is stored and executed on the server. Because the client never receives the compiled code file, the client has no opportunity to decompile it. If it is a concern, consider using an obfuscator that scrambles code to try to make it more difficult to understand. (For example, an obfuscator might rename all variables to have generic, meaningless names such as f__a__234.) Visual Studio includes a scaled-down version of one popular obfuscator, called Dotfuscator.

The following code shows the same console application in Visual Basic code:

Imports System

Namespace HelloWorld

Public Class TestClass

Shared Sub Main(args() As String)

Console.WriteLine("Hello World")

End Sub

End Class

End Namespace

If you compile this application and look at the IL code, you’ll find that it’s nearly identical to the IL code generated from the C# version. Although different compilers can sometimes introduce their own optimizations, as a general rule of thumb no .NET language outperforms any other .NET language, because they all share the same common infrastructure. This infrastructure is formalized in the CLS (Common Language Specification), which is described in the following sidebar, entitled “The Common Language Specification."

It’s worth noting that IL has been adopted as an ECMA and ISO standard. This adoption allows the adoption of other common language frameworks on other platforms. The Mono project at http://www.mono-project.com is the best example of such a project.

The Common Language Specification

The CLR expects all objects to adhere to a specific set of rules so that they can interact. The CLS is this set of rules.

The CLS defines many laws that all languages must follow, such as primitive types, method overloading, and so on. Any compiler that generates IL code to be executed in the CLR must adhere to all rules governed within the CLS. The CLS gives developers, vendors, and software manufacturers the opportunity to work within a common set of specifications for languages, compilers, and data types. You can find a list of a large number of CLS-compliant languages at http://dotnetpowered.com/languages.aspx.

Given these criteria, the creation of a language compiler that generates true CLR-compliant code can be complex. Nevertheless, compilers can exist for virtually any language, and chances are that there may eventually be one for just about every language you’d ever want to use. Imagine—mainframe programmers who loved COBOL in its heyday can now use their knowledge base to create web applications!

ASP.NET Fundamentals: ASP.NET is Compiled, Not Interpreted Language

Read

ASP.NET Fundamentals: ASP.NET is Compiled, Not Interpreted Language

ASP.NET applications, like all .NET applications, are always compiled. In fact, it’s impossible to execute C# or Visual Basic code without it being compiled first.

.NET applications actually go through two stages of compilation. In the first stage, the C# code you write is compiled into an intermediate language called Microsoft Intermediate Language (MSIL), or just IL. This first step is the fundamental reason that .NET can be language-interdependent. Essentially, all .NET languages (including C#, Visual Basic, and many more) are compiled into virtually identical IL code. This first compilation step may happen automatically when the page is first requested, or you can perform it in advance (a process known as pre-compiling). The compiled file with IL code is an assembly.

The second level of compilation happens just before the page is actually executed. At this point, the IL code is compiled into low-level native machine code. This stage is known as just-in-time (JIT) compilation, and it takes place in the same way for all .NET applications (including Windows applications, for example).

.NET compilation is decoupled into two steps in order to offer developers the most convenience and the best portability. Before a compiler can create low-level machine code, it needs to know what type of operating system and hardware platform the application will run on (for example, 32-bit or 64-bit Windows). By having two compile stages, you can create a compiled assembly with .NET code and still distribute this to more than one platform.

Of course, JIT compilation probably wouldn’t be that useful if it needed to be performed every time a user requested a web page from your site. Fortunately, ASP.NET applications don’t need to be compiled every time a web page is requested. Instead, the IL code is created once and regenerated only when the source is modified. Similarly, the native machine code files are cached in a system directory that has a path like c:\Windows\Microsoft.NET\Framework\[Version]\Temporary ASP.NET Files.

The actual point where your code is compiled to IL depends on how you’re creating and deploying your web application. If you’re building a web project in Visual Studio, the code is compiled to IL when you compile your project. But if you’re building a lighter-weight project less website, the code for each page is compiled the first time you request that page. Either way, the code goes through its second compilation step (from IL to machine code) the first time it’s executed.

ASP.NET also includes pre-compilation tools that you can use to compile your application right down to machine code once you’ve deployed it to the production web server. This allows you to avoid the overhead of first-time compilation when you deploy a finished application (and prevent other people from tampering with your code).

125 Basic C# Interview Questions and Answers

Read

125 Basic C# Interview Questions and Answers

Below is the list of 125 basic C# interview questions with their answers. These C# interview questions and answers are very simple and straight-forward which cover the basic concepts of C# mostly related to object oriented concepts. So if you are preparing for C# interview, I will suggest you to must go through these 125 C# basic interview questions and answers to revise your C# concepts. Here goes the list of 125 basic C# interview questions and answers.

1. What is C#?

C# (pronounced "C sharp") is a simple, modern, object-oriented, and type-safe programming language. It will immediately be familiar to C and C++ programmers. C# combines the high productivity of Rapid Application Development (RAD) languages.

2. What are the types of comment in C#?

There are 3 types of comments in C#.

Single line (//)

Multi (/* */)

Page/XML Comments (///).

3. What are the namespaces used in C#.NET?

Namespace is a logical grouping of class.

using System;

using System.Collections.Generic;

using System.Windows.Forms;

4. What are the characteristics of C#?

There are several characteristics of C# are :

Simple

Type safe

Flexible

Object oriented

Compatible

Consistent

Interoperable

Modern

5. What are the different categories of inheritance?

Inheritance in Object Oriented Programming is of four types:

Single inheritance: Contains one base class and one derived class.

Hierarchical inheritance: Contains one base class and multiple derived classes of the same base class.

Multilevel inheritance: Contains a class derived from a derived class.

Multiple inheritance: Contains several base classes and a derived class.

6. What are the basic concepts of object oriented programming?

It is necessary to understand some of the concepts used extensively in object oriented programming.These include:

Objects

Classes

Data abstraction and encapsulation

Inheritance

Polymorphism

Dynamic Binding

Message passing.

7. Can you inherit multiple interfaces?

Yes. Multiple interfaces may be inherited in C#.

8. What is inheritance?

Inheritance is deriving the new class from the already existing one.

9. Define scope?

Scope refers to the region of code in which a variable may be accessed.

10. What is the difference between public, static and void?

public: The keyword public is an access modifier that tells the C# compiler that the Main method is accessible by anyone.

static: The keyword static declares that the Main method is a global one and can be called without creating an instance of the class. The compiler stores the address of the method as the entry point and uses this information to begin execution before any objects are created.

void: The keyword void is a type modifier that states that the Main method does not return any value.

11. What are the modifiers in C#?

Abstract

Sealed

Virtual

Const

Event

Extern

Override

Readonly

Static

New

12. What are the types of access modifiers in C#?

Access modifiers in C# are :

public

protect

private

internal

internal protect

13. What is boxing and unboxing?

Implicit conversion of value type to reference type of a variable is known as BOXING, for example integer to object type conversion.

Conversion of reference type variable back to value type is called as UnBoxing.

14. What is object?

An object is an instance of a class. An object is created by using operator new. A class that creates an object in memory will contain the information about the values and behaviors (or methods) of that specific object.

15. Where are the types of arrays in C#?

Single-Dimensional

Multidimensional

Jagged arrays.

16. What is the difference between Object and Instance?

An instance of a user-defined type is called an object. We can instantiate many objects from one class.

An object is an instance of a class.

17. Define destructors?

A destructor is called for a class object when that object passes out of scope or is explicitly deleted.A destructors as the name implies is used to destroy the objects that have been created by a constructors.Like a constructor , the destructor is a member function whose name is the same as the class name but is precised by a tilde.

18. What is the use of enumerated data type?

An enumerated data type is another user defined type which provides a way for attaching names to numbers thereby increasing comprehensibility of the code. The enum keyword automatically enumerates a list of words by assigning them values 0,1,2, and so on.

19. Define Constructors?

A constructor is a member function with the same name as its class. The constructor is invoked whenever an object of its associated class is created.It is called constructor because it constructs the values of data members of the class.

20. What is encapsulation?

The wrapping up of data and functions into a single unit (called class) is known as encapsulation. Encapsulation containing and hiding information about an object, such as internal data structures and code.

21.Does c# support multiple inheritance?

No,its impossible which accepts multi level inheritance.

22. What is ENUM?

Enum are used to define constants.

23. What is a data set?

A DataSet is an in memory representation of data loaded from any data source.

24. What is the difference between private and public keyword?

Private: The private keyword is the default access level and most restrictive among all other access levels. It gives least permission to a type or type member. A private member is accessible only within the body of the class in which it is declared.

Public: The public keyword is most liberal among all access levels, with no restrictions to access what so ever. A public member is accessible not only from within, but also from outside, and gives free access to any member declared within the body or outside the body.

25. Define polymorphism?

Polymorphism means one name, multiple forms. It allows us to have more than one function with the same name in a program. It allows us to have overloading of operators so that an operation can exhibit different behaviors in different instances.

26. What is Jagged Arrays?

A jagged array is an array whose elements are arrays.

The elements of a jagged array can be of different dimensions and sizes.

A jagged array is sometimes called an array–of–arrays.

27. What is an abstract base class?

An abstract class is a class that is designed to be specifically used as a base class. An abstract class contains at least one pure virtual function.

28. How is method overriding different from method overloading?

When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.

29. What is the difference between ref & out parameters?

An argument passed to a ref parameter must first be initialized. Compare this to an out parameter, whose argument does not have to be explicitly initialized before being passed to an out parameter.

30. What is the use of using statement in C#?

The using statement is used to obtain a resource, execute a statement, and then dispose of that resource.

31.What is serialization?

Serialization is the process of converting an object into a stream of bytes.

De-serialization is the opposite process of creating an object from a stream of bytes.

Serialization / De-serialization is mostly used to transport objects.

32. What are the difference between Structure and Class?

Structures are value type and Classes are reference type

Structures can not have contractors or destructors.

Classes can have both contractors and destructors.

Structures do not support Inheritance, while Classes support Inheritance.

33. What is difference between Class And Interface?

Class is logical representation of object. It is collection of data and related sub procedures with defination.

Interface is also a class containg methods which is not having any definations.Class does not support multiple inheritance. But interface can support.

34. What is Delegates?

Delegates are a type-safe, object-oriented implementation of function pointers and are used in many situations where a component needs to call back to the component that is using it.

35. What is Authentication and Authorization?

Authentication is the process of identifying users. Authentication is identifying/validating the user against the credentials (username and password).

Authorization performs after authentication. Authorization is the process of granting access to those users based on identity.

Authorization allowing access of specific resource to user.

36. What is a base class?

A class declaration may specify a base class by following the class name with a colon and the name of the base class. omitting a base class specification is the same as deriving from type object.

37. Can “this” be used within a static method?

No ‘This’ cannot be used in a static method. As only static variables/methods can be used in a static method.

38. What is difference between constants, readonly and, static ?

Constants: The value can’t be changed.

Read-only: The value will be initialized only once from the constructor of the class.

Static: Value can be initialized once.

39. What are the different types of statements supported in C#?

C# supports several different kinds of statements are

Block statements

Declaration statements

Expression statements

Selection statements

Iteration statements

Jump statements

Try catch statements

Checked and unchecked

Lock statement

40. What is an interface class?

It is an abstract class with public abstract methods all of which must be implemented in the inherited classes.

41.What are value types and reference types?

Value types are stored in the Stack.

Examples : bool, byte, chat, decimal, double, enum , float, int, long, sbyte, short, strut, uint, ulong, ushort.

Reference types are stored in the Heap.

Examples : class, delegate, interface, object, string.

42. What is the difference between string keyword and System.String class?

String keyword is an alias for Syste.String class. Therefore, System.String and string keyword are the same, and you can use whichever naming convention you prefer. The String class provides many methods for safely creating, manipulating, and comparing strings.

43. What are the two data types available in C#?

Value type

Reference type

44. What are the different types of Caching?

There are three types of Caching:

Output Caching: stores the responses from an asp.net page.

Fragment Caching: Only caches/stores the portion of page (User Control)

Data Caching: is Programmatic way to Cache objects for performance.

45. What is the difference between Custom Control and User Control?

Custom Controls are compiled code (Dlls), easier to use, difficult to create, and can be placed in toolbox. Drag and Drop controls.

Attributes can be set visually at design time. Can be used by Multiple Applications (If Shared Dlls), Even if Private can copy to bin directory of web application add reference and use. Normally designed to provide common functionality independent of consuming Application.

User Controls are similar to those of ASP include files, easy to create, can not be placed in the toolbox and dragged - dropped from it. A User Control is shared among the single application files.

46. What is methods?

A method is a member that implements a computation or action that can be performed by an object or class. Static methods are accessed through the class. Instance methods are accessed through instances of the class.

47. What is fields?

A field is a variable that is associated with a class or with an instance of a class.

48. What is events?

An event is a member that enables a class or object to provide notifications. An event is declared like a field except that the declaration includes an event keyword and the type must be a delegate type.

49. What is literals and their types?

Literals are value constants assigned to variables in a program. C# supports several types of literals are

Integer literals

Real literals

Boolean literals

Single character literals

String literals

Backslash character literals

50. What is the difference between value type and reference type?

Value types are stored on the stack and when a value of a variable is assigned to another variable.

Reference types are stored on the heap, and when an assignment between two reference variables occurs.

51. What are the features of c#?

C# is a simple and powerful programming language for writing enterprise edition applications.

This is a hybrid of C++ and VB. It retains many C++ features in the area statements,expressions, and operators and incorporated the productivity of VB.

C# helps the developers to easily build the web services that can be used across the Internet through any language, on any platform.

C# helps the developers accomplishing with fewer lines of code that will lead to the fewer errors in the code.

C# introduces the considerable improvement and innovations in areas such as type safety,versioning. events and garbage collections.

52. What are the types of errors?

Syntax error

Logic error

Runtime error

53. What is the difference between break and continue statement?

The break statement is used to terminate the current enclosing loop or conditional statements in which it appears. We have already used the break statement to come out of switch statements.

The continue statement is used to alter the sequence of execution. Instead of coming out of the loop like the break statement did, the continue statement stops the current iteration and simply returns control back to the top of the loop.

54. Define namespace?

The namespace are known as containers which will be used to organize the hierarchical set of .Net classes.

55. What is a code group?

A code group is a set of assemblies that share a security context.

56. What are sealed classes in C#?

The sealed modifier is used to prevent derivation from a class. A compile-time error occurs if a sealed class is specified as the base class of another class.

57. What is the difference between static and instance methods?

A method declared with a static modifier is a static method. A static method does not operate on a specific instance and can only access static members.

A method declared without a static modifier is an instance method. An instance method operates on a specific instance and can access both static and instance members. The instance on which an instance method was invoked can be explicitly accessed as this. It is an error to refer to this in a static method.

58. What are the different types of variables in C#?

Different types of variables used in C# are :

static variables

instance variable

value parameters

reference parameters

array elements

output parameters

local variables

59. What is meant by method overloading?

Method overloading permits multiple methods in the same class to have the same name as long as they have unique signatures. When compiling an invocation of an overloaded method, the compiler uses overload resolution to determine the specific method to invoke.

60. What is parameters?

Parameters are used to pass values or variable references to methods. The parameters of a method get their actual values from the arguments that are specified when the method is invoked. There are four kinds of parameters: value parameters, reference parameters, output parameters, and parameter arrays.

61. Is C# is object oriented?

Yes, C# is an OO langauge in the tradition of Java and C++.

62. What is the difference between Array and Arraylist?

An array is a collection of the same type. The size of the array is fixed in its declaration. A linked list is similar to an array but it doesn’t have a limited size.

63. What are the special operators in C#?

C# supports the following special operators.

is (relational operator)

as (relational operator)

typeof (type operator)

sizeof (size operator)

new (object creator)

.dot (member access operator)

checked (overflow checking)

unchecked (prevention of overflow checking)

64. What is meant by operators in c#?

An operator is a member that defines the meaning of applying a particular expression operator to instances of a class. Three kinds of operators can be defined: unary operators, binary operators, and conversion operators. All operators must be declared as public and static.

65. What is a parameterized type?

A parameterized type is a type that is parameterized over another value or type.

66. What are the features of abstract class?

An abstract class cannot be instantiated, and it is an error to use the new operator on an abstract class.

An abstract class is permitted (but not required) to contain abstract methods and accessors.

An abstract class cannot be scaled.

67. What is the use of abstract keyword?

The modifier abstract is a keyword used with a class, to indicate that this class cannot itself have direct instances or objects, and it is intended to be only a 'base' class to other classes.

68. What is the use of goto statement?

The goto statement is also included in the C# language. This goto can be used to jump from inside a loop to outside. But jumping from outside to inside a loop is not allowed.

69. What is the difference between console and window application?

A console application, which is designed to run at the command line with no user interface.

A Windows application, which is designed to run on a user’s desktop and has a user interface.

70. What is the use of return statement?

The return statement is associated with procedures (methods or functions). On executing the return statement, the system passes the control from the called procedure to the calling procedure. This return statement is used for two purposes :

to return immediately to the caller of the currently executed code

to return some value to the caller of the currently executed code.

71. What is the difference between Array and LinkedList?

Array is a simple sequence of numbers which are not concerned about each others positions. they are independent of each others positions. adding,removing or modifying any array element is very easy. Compared to arrays ,linked list is a comlicated sequence of numbers.

72. Does C# have a throws clause?

No, unlike Java, C# does not require the developer to specify the exceptions that a method can throw.

73. Does C# support a variable number of arguments?

Yes, uisng the params keyword. The arguments are specified as a list of arguments of a specific type.

74. Can you override private virtual methods?

No, private methods are not accessible outside the class.

75. What is a multi cast delegates?

Each delegate object holds reference to a single method. However, it is possible for a delegate object to hold references of and invoke multiple methods. Such delegate objects are called multicast delegates or combinable delegates.

76. Which is an exclusive feature of C#?

Xml documentation.

77. Is using of exceptions in C# recommended?

Yes, exceptions are the recommended error handling mechanism in .NET Framework.

78. What does a break statement do in switch statements?

The break statement terminates the loop in which it exists. It also changes the flow of the execution of a program.

In switch statements, the break statement is used at the end of a case statement. The break statement is mandatory in C# and it avoids the fall through of one case statement to another.

79. Is C# object oriented?

Yes, C# is an OO language in the tradition of java and C++.

80. What is smart navigation?

The cursor position is maintained when the page gets refreshed due to the server side validation and the page gets refreshed.

81. What is the difference between CONST and READONLY?

Both are meant for constant values. A const field can only be initialized at the declaration of the field. A readonly field can be initialized either at the declaration or.

82. Does C# have a throws clause?

No, unlike Java, C# does not require (or even allow) the developer to specify the exceptions that a method can throw.

83. What are the different ways a method can be overloaded?

Different parameter data types, different number of parameters, different order of parameters.

84. Do events have return type?

No, events do not have return type.

85. What is event?

An event is an action performed based on another method of the program.

An event is a delegate type dass member that is used by an object or a class to provide a notification to other objects that an event has occurred.

An event can be declared with the help of the event keyword.

86. What is an identifier?

Identifiers are nothing but names given to various entities uniquely identified in a program.

87. What are the different types of literals in C#?

Boolean literals: True and False are literals of the Boolean type that map to the true and false state, respectively.

Integer literals: Used to write values of types Int, ulnt, long, and ulong.

Real literals: Used to write values of types float, double, and dedmal.

Character literals: Represents a single character and usually consists of a character in quotes, such as 'a'.

String literals: C# supports two types of string literals, regular string literal and verbatim string literals. A regular string literal consists of zero or more characters enclosed in double quotes, such as "116110". A verbatim string literal consists of an @ character followed by a double–quote character, such as ©"hello".

The Null literal: Represents the null–type.

88. What is meant by data encapsulation?

Data encapsulation, also referred to as data hiding, is the mechanism whereby the implementation details of a class are kept hidden from the user. The user can only perform a restricted set of operations on the hidden members of the class by executing special functions called methods.

89. Can you override private virtual methods?

No. Private methods are not accessible outside the class.

90. What is the main difference between a subprocedure and a function?

Subprocedures do not return a value, while functions do.

91. How does C# differ from C++?

C# does not support #include statement. It uses only using statement.

In C# , class definition does not use a semicolon at the end.

C# does not support multiple code inheritance.

Casting in C# is much safer than in c++.

In C# switch can also be used on string values.

Command line parameters array behave differently in C# as compared to C++.

92. What is nested class?

A Nested classes are classes within classes.

A nested class is any class whose declaration occurs within the body of another class or interface.

93. Can you have parameters for static constructors?

No, static constructors cannot have parameters.

94. Is String is Value Type or Reference Type in C#?

String is an object(Reference Type).

95. Does C# provide copy constructor?

No, C# does not provide copy constructor.

96. Can a class or a struct have multiple constructors?

Yes, a class or a struct can have multiple constructors. Constructors in C# can be overloaded.

97. Can you create an instance of an interface?

No, you cannot create an instance of an interface.

98. Can an Interface contain fields?

No, an Interface cannot contain fields.

99. Can a class have static constructor?

Yes, a class can have static constructor. Static constructors are called automatically, immediately before any static fields are accessed, and are generally used to initialize static class members. It is called automatically before the first instance is created or any static members are referenced. Static constructors are called before instance constructors. An example is shown below.

100. What is the main use of delegates in C#?

Delegates are mainly used to define call back methods.

101. What is the difference between Shadowing and Overriding?

Overriding redefines only the implementation while shadowing redefines the whole element.

In overriding derived classes can refer the parent class element by using "ME" keyword, but in shadowing you can access it by "MYBASE".

102. Can events have access modifiers?

Yes, you can have access modifiers in events. You can have events with the protected keyword, which will be accessible only to inherited classes. You can have private events only for objects in that class.

103. Why is the virtual keyword used in code?

The Virtual keyword is used in code to define methods and the properties that can be overridden in derived classes.

104. What are constructors and destructors?

Constructors and destructors are special methods.

Constructors and destructors are special methods of every class.

Each class has its own constructor and destructor and are called automatically when the instance of a class is created or destroyed.

The constructor initializes all class members whenever you access the class and the destructor destroys them when the objects are not required anymore.

105. How can we suppress a finalize method?

GC.SuppressFinalize()

106. Does C# support a variable number of arguments?

Yes, using the params keyword.

The arguments are specified as a list of arguments of a specific type, e.g., int. For ultimate flexibility, the type can be object.

The standard example of a method which uses this approach is System.console.writeLine().

107.Which method will you call to start a thread?

Start

108. What is Generic?

Generic help us to create flexible strong type collection.

Generic basically seperate the logic from the datatype in order maintain better reusability, better maintainability etc.

109. What are the different types of polymorphism?

There are two types of polymorphism. They are:

Compile time Polymorphism

Run time Polymorphism

110. What is the difference between compile time polymorphism and run time polymorphism?

Compile time Polymorphism

Compile time Polymorphism also known as method overloading.

Method overloading means having two or more methods with the same name but with different signatures.

Run time Polymorphism

Run time Polymorphism also known as method overriding.

Method overriding means having two or more methods with the same name , same signature but with different implementation.

111. Which namespace enables multithreaded programming in XML?

System.Threading

112. Can we declare a block as static in c#?

No, because c# doesnot support static block, but it supports static method.

113. Can we declare a method as sealed?

In C# a method can't be declared as sealed. However when we override a method in a derived class, we can declare the overridden method as sealed. By declaring it as sealed, we can avoid further overriding of this method.

114. What Command is used to implement properties in C#?

get & set access modifiers are used to implement properties in c#.

115. What is static member?

The member defined as static which can be invoked directly from the class level, rather than from its instance.

116. What is the syntax to inherit from a class in C#?

When a class is derived from another class, then the members of the base class become the members of the derived class.

The access modifier used while accessing members of the base class specifies the access status of the base class members inside the derived class.

The syntax to inherit a class from another class In C# is as follows:

class MyNewClass : MyBaseClass

117. What is a basic difference between the while loop and do while loop in C#?

The while loop tests its condition at the beginning, which means that the enclosed set of statements run for zero or more number of times if the condition evaluates to true. The do while loop iterates a set of statements at least once and then checks the condition at the end.

118. What is the main difference between a subprocedure and a function?

Subprocedures do not return a value, while functions do.

119. What are sealed classes in c#?

The sealed modifier is used to prevent derivation from a class.

A compile time error occurs if a sealed class is specified as the base class of another class.

120. What is the difference between class and an Interface?

Abstract classes can have implementations for some of its members, but the interface can't have implementation for any of its members.

Interfaces cannot have fields where as an abstract class can have fields.

An interface can inherit from another interface only and cannot inherit from an abstract class, where as an abstract class can inherit from another abstract class or another interface.

A class can inherit from multiple interfaces at the same time, where as a class cannot inherit from multiple classes at the same time.

Abstract class members can have access modifiers where as interface members cannot have access modifiers.

121. What is the difference between an abstract method & virtual method?

An Abstract method does not provide an implementation and forces overriding to the deriving class (unless the deriving class also an abstract class), where as the virtual method has an implementation and leaves an option to override it in the deriving class. Thus Virtual method has an implementation & provides the derived class with the option of overriding it. Abstract method does not provide an implementation & forces the derived class to override the method.

122. What is Static Method?

It is possible to declare a method as Static provided that they don't attempt to access any instance data or other instance methods.

123. What is a New modifier?

The new modifier hides a member of the base class. C# supports only hide by signature.

124. What are the advantages of get and set properties in C#?

The get property accessor is used to return the property value.

The set property accessor is used to assign a new value.

125. What are the difference between const and readonly?

A const can not be static, while readonly can be static.

A const need to be declared and initialized at declaration only, while a readonly can be initialized at declaration or by the code in the constructor.

A const's value is evaluated at design time, while a readonly's value is evaluated at runtime.