Interview Questions and Answer On

8/6/2019 Interview Questions and Answer On

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C# Frequently Asked Interview Questions and Answers

1. Wh

ats th

e implicit name of th

e parameter th

at gets passed into th

e class setmethod? Value, and its datatype depends on whatever variable were changing.

2. How do you inherit from a class in C#? Place a colon and then the name of the baseclass. Notice that its double colon in C++.

3. Does C# support multiple inheritance?No, use interfaces instead.4. When you inherit a protected class-level variable, who is it available to? Classes in

the same namespace.

5. Are private class-level variables inherited? Yes, but they are not accessible, so lookingat it you can honestly say that they are not inherited. But they are.

6. Describe the accessibility modifier protected internal. Its available to derived classesand classes within the same Assembly (and naturally from the base class its declared in).

7. C# provides a default constructor for me. I write a constructor that takes a string asa parameter, but want to keep the no parameter one. How many constructors

should I write? Two. Once you write at least one constructor, C# cancels the freebie

constructor, and now you have to write one yourself, even if theres no implementation in

it.

8. Whats the top .NET class that everything is derived from? System.Object.9. Hows method overriding different from overloading? When overriding, you change

the method behavior for a derived class. Overloading simply involves having a method

with the same name within the class.

10.What does the keyword virtual mean in the method definition? The method can beover-ridden.

11.Can you declare the override method static while the original method is non-static?No, you cant, the signature of the virtual method must remain the same, only the

keyword virtual is changed to keyword override.

12.Can you override private virtual methods?No, moreover, you cannot access privatemethods in inherited classes, have to be protected in the base class to allow any sort of

access.


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13.Can you prevent your class from being inherited and becoming a base class for someother classes?Yes, thats what keyword sealed in the class definition is for. The

developer trying to derive from your class will get a message: cannot inherit from Sealed

class WhateverBaseClassName. Its the same concept as final class in Java.

14.Can you allow class to be inherited, but prevent the method from being over-ridden? Yes, just leave the class public and make the method sealed.

15.Whats an abstract class? A class that cannot be instantiated. A concept in C++ knownas pure virtual method. A class that must be inherited and have the methods over-ridden.

Essentially, its a blueprint for a class without any implementation.

16.When do you absolutely have to declare a class as abstract (as opposed to free-willededucated choice or decision based on UML diagram)? When at least one of the

methods in the class is abstract. When the class itself is inherited from an abstract class,

but not all base abstract methods have been over-ridden.

17.Whats an interface class? Its an abstract class with public abstract methods all ofwhich must be implemented in the inherited classes.

18.Why cant you specify the accessibility modifier for methods inside the interface?They all must be public. Therefore, to prevent you from getting the false impression that

you have any freedom of choice, you are not allowed to specify any accessibility, its

public by default.

19.Can you inherit multiple interfaces? Yes, why not.20.And if they have conflicting method names? Its up to you to implement the method

inside your own class, so implementation is left entirely up to you. This might cause a

problem on a higher-level scale if similarly named methods from different interfaces

expect different data, but as far as compiler cares youre okay.

21.Whats the difference between an interface and abstract class? In the interface allmethods must be abstract; in the abstract class some methods can be concrete. In the

interface no accessibility modifiers are allowed, which is ok in abstract classes.

22.How can you overload a method? Different parameter data types, different number ofparameters, different order of parameters.

23.If a base class has a bunch of overloaded constructors, and an inherited class hasanother bunch of overloaded constructors, can you enforce a call from an inherited


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constructor to an arbitrary base constructor? Yes, just place a colon, and then

keyword base (parameter list to invoke the appropriate constructor) in the overloaded

constructor definition inside the inherited class.

24.Whats the difference between System.String and System.StringBuilder classes?System.String is immutable; System.StringBuilder was designed with the purpose of

having a mutable string where a variety of operations can be performed.

25.Whats the advantage of using System.Text.StringBuilder over System.String?StringBuilder is more efficient in the cases, where a lot of manipulation is done to the

text. Strings are immutable, so each time its being operated on, a new instance is created.

26.Can you store multiple data types in System.Array?No.27.Whats the difference between the System.Array.CopyTo() and

System.Array.Clone()? The first one performs a deep copy of the array, the second one

is shallow.

28.How can you sort the elements of the array in descending order? By calling Sort()and then Reverse() methods.

29.Whats the .NET datatype that allows the retrieval of data by a unique key?ashTable.

30.Whats class SortedList underneath? A sorted HashTable.31.Willfinally block get executed if the exception had not occurred? Yes.32.Whats the C# equivalent of C++ catch (), which was a catch-all statement for any

possible exception? A catch block that catches the exception of type System.Exception.

You can also omit the parameter data type in this case and just write catch {}.

33.Can multiple catch blocks be executed?No, once the proper catch code fires off, thecontrol is transferred to the finally block (if there are any), and then whatever follows the

finally block.

34.Why is it a bad idea to throw your own exceptions? Well, if at that point you knowthat an error has occurred, then why not write the proper code to handle that error instead

of passing a new Exception object to the catch block? Throwing your own exceptions

signifies some design flaws in the project.

35.Whats a delegate? A delegate object encapsulates a reference to a method. In C++ theywere referred to as function pointers.


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36.Whats a multicast delegate? Its a delegate that points to and eventually fires offseveral methods.

37.Hows the DLL Hell problem solved in .NET? Assembly versioning allows theapplication to specify not only the library it needs to run (which was available under

Win32), but also the version of the assembly.

38.What are the ways to deploy an assembly? An MSI installer, a CAB archive, andXCOPY command.

39.Whats a satellite assembly? When you write a multilingual or multi-culturalapplication in .NET, and want to distribute the core application separately from the

localized modules, the localized assemblies that modify the core application are called

satellite assemblies.

40.What namespaces are necessary to create a localized application?System.Globalization, System.Resources.

41.Whats the difference between // comments, /* */ comments and /// comments?Single-line, multi-line and XML documentation comments.

42.How do you generate documentation from the C# file commented properly with acommand-line compiler? Compile it with a /doc switch.

43.Whats the difference between and XML documentation tag? Single line code exampleand multiple-line code example.

44.Is XML case-sensitive? Yes, so and are different elements.45.What debugging tools come with the .NET SDK? CorDBG command-line debugger,

and DbgCLR graphic debugger. Visual Studio .NET uses the DbgCLR. To use

CorDbg, you must compile the original C# file using the /debug switch.

46.What does the This window show in the debugger? It points to the object thatspointed to by this reference. Objects instance data is shown.

47.What does assert() do? In debug compilation, assert takes in a Boolean condition as aparameter, and shows the error dialog if the condition is false. The program proceeds

without any interruption if the condition is true.

48.Whats the difference between the Debug class and Trace class? Documentationlooks the same. Use Debug class for debug builds, use Trace class for both debug and

release builds.


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49.Why are there five tracing levels in System.Diagnostics.TraceSwitcher? The tracingdumps can be quite verbose and for some applications that are constantly running you run

the risk of overloading the machine and the hard drive there. Five levels range from None

to Verbose, allowing to fine-tune the tracing activities.

50.Where is the output of TextWriterTraceListener redirected? To the Console or a textfile depending on the parameter passed to the constructor.

51.How do you debug an ASP.NET Web application? Attach the aspnet_wp.exe processto the DbgClr debugger.

52.What are three test cases you should go through in unit testing? Positive test cases(correct data, correct output), negative test cases (broken or missing data, proper

handling), exception test cases (exceptions are thrown and caught properly).

53.Can you change the value of a variable while debugging a C# application? Yes, ifyou are debugging via Visual Studio.NET, just go to Immediate window.

54.Explain the three services model (three-tier application). Presentation (UI), business(logic and underlying code) and data (from storage or other sources).

55.What are advantages and disadvantages of Microsoft-provided data providerclasses in ADO.NET? SQLServer.NET data provider is high-speed and robust, but

requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for

accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but its a

.NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a

deprecated layer provided for backward compatibility to ODBC engines.

56.Whats the role of the DataReader class in ADO.NET connections? It returns a read-only dataset from the data source when the command is executed.

57.What is the wildcard character in SQL? Lets say you want to query database withLIKE for all employees whose name starts with La. The wildcard character is %, the

proper query with LIKE would involve La%.

58.Explain ACID rule of thumb for transactions. Transaction must be Atomic (it is oneunit of work and does not dependent on previous and following transactions), Consistent

(data is either committed or roll back, no in-between case where something has been

updated and something hasnt), Isolated (no transaction sees the intermediate results of


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the current transaction), Durable (the values persist if the data had been committed even

if the system crashes right after).

59.What connections does Microsoft SQL Server support? Windows Authentication (viaActive Directory) and SQL Server authentication (via Microsoft SQL Server username

and passwords).

60.Which one is trusted and which one is untrusted? Windows Authentication is trustedbecause the username and password are checked with the Active Directory, the SQL

Server authentication is untrusted, since SQL Server is the only verifier participating in

the transaction.

61.Why would you use untrusted verificaion? Web Services might use it, as well as non-Windows applications.

62.What does the parameter Initial Catalog define inside Connection String? Thedatabase name to connect to.

63.Whats the data provider name to connect to Access database? Microsoft.Access.64.What does Dispose method do with the connection object? Deletes it from the

memory.

65.What is a pre-requisite for connection pooling? Multiple processes must agree thatthey will share the same connection, where every parameter is the same, including the

security settings.

1. Whats the implicit name of the parameter that gets passed into the class setmethod?

Value, and its datatype depends on whatever variable were changing.

2. How do you inherit from a class in C#?

Place a colon and then the name of the base class. Notice that its double colon in

C++.


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3. When you inherit a protected class-level variable, who is it available to?

Classes in the same namespace.

4. Are private class-level variables inherited?

Yes, but they are not accessible, so looking at it you can honestly say that they are not

inherited. But they are.

5. Describe the accessibility modifier protected internal.

Its available to derived classes and classes within the same Assembly (and naturally

from the base class its declared in).

6. C# provides a default constructor for me. I write a constructor that takes a

string as a parameter, but want to keep the no parameter one. How many

constructors should I write?

Two. Once you write at least one constructor, C# cancels the freebie constructor, and

now you have to write one yourself, even if theres no implementation in it.

7.Whats the top .NET class that everything is derived from?

System.Object.

8. Hows method overriding different from overloading?

When overriding, you change the method behavior for a derived class. Overloading

simply involves having a method with the same name within the class.

9.What does the keyword virtual mean in the method definition?

The method can be over-ridden.

10. Can you declare the override method static while the original method is non-

static?

No, you cant, the signature of the virtual method must remain the same, only the


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keyword virtual is changed to keyword override.

11. Can you override private virtual methods?

No, moreover, you cannot access private methods in inherited classes, have to be

protected in the base class to allow any sort of access.

12. Can you prevent your class from being inherited and becoming a base class

for some other classes?

Yes, thats what keyword sealed in the class definition is for. The developer trying to

derive from your class will get a message: cannot inherit from Sealed class

WhateverBaseClassName. Its the same concept as final class in Java.

13. Can you allow class to be inherited, but prevent the method from being over-

ridden?

Yes, just leave the class public and make the method sealed.

14.Whats an abstract class?

A class that cannot be instantiated. A concept in C++ known as pure virtual method.

A class that must be inherited and have the methods over-ridden. Essentially, its a

blueprint for a class without any implementation.

15.When do you absolutely have to declare a class as abstract (as opposed to

free-willed educated choice or decision based on UML diagram)?

When at least one of the methods in the class is abstract. When the class itself is

inherited from an abstract class, but not all base abstract methods have been over-

ridden.

16.Whats an interface class?

Its an abstract class with public abstract methods all of which must be implemented

in the inherited classes.


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17.Why cant you specify the accessibility modifier for methods inside the

interface?

They all must be public. Therefore, to prevent you from getting the false impression

that you have any freedom of choice, you are not allowed to specify any accessibility,

its public by default.

18. And if they have conflicting method names?

Its up to you to implement the method inside your own class, so implementation is

left entirely up to you. This might cause a problem on a higher-level scale if similarly

named methods from different interfaces expect different data, but as far as compiler

cares youre okay.

19.Whats the difference between an interface and abstract class?

In the interface all methods must be abstract; in the abstract class some methods can

be concrete. In the interface no accessibility modifiers are allowed, which is ok in

abstract classes.

20. How can you overload a method?

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

parameters.

21. If a base class has a bunch of overloaded constructors, and an inherited class

has another bunch of overloaded constructors, can you enforce a call from an

inherited constructor to an arbitrary base constructor?

Yes, just place a colon, and then keyword base (parameter list to invoke the

appropriate constructor) in the overloaded constructor definition inside the inherited

class.

22. Whats the difference between System.String and System.StringBuilder

classes? System.String is immutable; System.StringBuilder was designed with the

purpose of having a mutable string where a variety of operations can be performed.


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23. Whats the advantage of using System.Text.StringBuilder over

System.String?StringBuilder is more efficient in the cases, where a lot of

manipulation is done to the text. Strings are immutable, so each time its being

operated on, a new instance is created.

24. Can you store multiple data types in System.Array?

No.

25.Whats the difference between the System.Array.CopyTo() and

System.Array.Clone()?

The first one performs a deep copy of the array, the second one is shallow.

26. How can you sort the elements of the array in descending order?

By calling Sort() and then Reverse() methods.

27.Whats the .NET datatype that allows the retrieval of data by a unique key?

HashTable.

28.Whats class SortedList underneath?

A sorted HashTable.

29.Will finally block get executed if the exception had not occurred?

Yes.

30. Can multiple catch blocks be executed?

No, once the proper catch code fires off, the control is transferred to the finally block (if there are

any), and then whatever follows the finally block.

31.Why is it a bad idea to throw your own exceptions?


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Well, if at that point you know that an error has occurred, then why not write the proper code to

handle that error instead of passing a new Exception object to the catch block? Throwing your

own exceptions signifies some design flaws in the project.

32. Whats a delegate?

A delegate object encapsulates a reference to a method. In C++ they were referred to as function

pointers.

33. Whats a multicast delegate?

Its a delegate that points to and eventually fires off several methods.

34. Hows the DLL Hell problem solved in .NET?

Assembly versioning allows the application to specify not only the library it needs to run (which

was available underWin32), but also the version of the assembly.

35.What are the ways to deploy an assembly?

An MSI installer, a CAB archive, and XCOPY command.

36. Whats a satellite assembly?

When you write a multilingual or multi-cultural application in .NET, and want to distribute the

core application separately from the localized modules, the localized assemblies that modify the

core application are called satellite assemblies.

37. What namespaces are necessary to create a localized application?System.Globalization,

System.Resources.

38. How do you generate documentation from the C# file commented properly with a

command-line compiler?

Compile it with a /doc switch.

39. Whats the difference between and XML documentation tag?


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Single line code example and multiple-line code example.

40. Is XML case-sensitive?Yes, so and are different elements.

41.What debugging tools come with the .NET SDK?

CorDBG command-line debugger, and DbgCLR graphic debugger. Visual Studio .NET uses

the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.

42. What does the This window show in the debugger?

It points to the object thats pointed to by this reference. Objects instance data is shown.

43. What does assert() do?

In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error

dialog if the condition is false. The program proceeds without any interruption if the condition is

true.

44.Whats the difference between the Debug class and Trace class?

Documentation looks the same. Use Debug class for debug builds, use Trace class for both

debug and release builds.

45.Why are there five tracing levels in System.Diagnostics.TraceSwitcher?

The tracing dumps can be quite verbose and for some applications that are constantly running

you run the risk of overloading the machine and the hard drive there. Five levels range from

None to Verbose, allowing to fine-tune the tracing activities.

46.Where is the output of TextWriterTraceListener redirected?

To the Console or a text file depending on the parameter passed to the constructor.

47. How do you debug an ASP.NET Web application?

Attach the aspnet_wp.exe process to the DbgClr debugger.


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48.What are three test cases you should go through in unit testing?

Positive test cases (correct data, correct output), negative test cases (broken or missing data,

proper handling), exception test cases (exceptions are thrown and caught properly).

49. Can you change the value of a variable while debugging a C# application?Yes, if you

are debugging via Visual Studio.NET, just go to Immediate window.

50. Explain the three services model (three-tier application). Presentation (UI), business (logic

and underlying code) and data (from storage or other sources).

51.What are advantages and disadvantages of Microsoft-provided data provider classes in

ADO.NET?

SQLServer.NET data provider is high-speed and robust, but requires SQL Server license

purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle,

DB2, Microsoft Access and Informix, but its a .NET layer on top of OLE layer, so not the

fastest thing in the world. ODBC.NET is a deprecated

layer provided for backward compatibility to ODBC engines.

52. Whats the role of the DataReader class in ADO.NET connections?

It returns a read-only dataset from the data source when the command is executed.

53. What is the wildcard character in SQL?

Lets say you want to query database with LIKE for all employees whose name starts with La.

The wildcard character is %, the proper query with LIKE would involve La%.

54. Explain ACID rule of thumb for transactions.

Transaction must be Atomic (it is one unit of work and does not dependent on previous and

following transactions), Consistent (data is either committed or roll back, no in-between case

where something has been updated and something hasnt), Isolated (no transaction sees the

intermediate results of the current transaction), Durable (the values persist if the data had been

committed even if the system crashes right after).


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55.What connections does Microsoft SQL Server support?

Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft

SQL Server username and passwords).

56.Which one is trusted and which one is untrusted?

Windows Authentication is trusted because the username and password are checked with the

Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only

verifier participating in the transaction.

57.Why would you use untrusted verificaion?

Web Services might use it, as well as non-Windows applications.

58.What does Dispose method do with the connection object?

Deletes it from the memory.

59.What is a pre-requisite for connection pooling?

Multiple processes must agree that they will share the same connection, where every parameter

is the same, including the security settings.

1. How big is the datatype int in .NET? 32 bits.

2. How big is the char? 16 bits (Unicode).

3. How do you initiate a string without escaping each backslash? Put an @ sign in front of

the double-quoted string.

4.What are valid signatures for the Main function?

l public static void Main()

l public static int Main()


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l public static void Main( string[] args )

l public static int Main(string[] args )

5. How do you initialize a two-dimensional array that you dont know the dimensions of?

l int [, ] myArray; //declaration

l myArray= new int [5, 8]; //actualinitialization

6.Whats the access level of the visibility type internal? Current assembly.

7.Whats the difference between struct and class in C#?

l Structscannot be inherited.

l Structsare passed by value, not by reference.

l Struct is stored on the stack, not the heap.

8. Explain encapsulation. The implementation is hidden, the interface is exposed.

9.What data type should you use if you want an 8-bit value thats signed? sbyte.

10. Speaking of Boolean data types, whats different between C# and C/C++? Theres no

conversion between 0 and false, as well as any other number and true, like in C/C++.

11.Where are the value-type variables allocated in the computer RAM? Stack.

12.Where do the reference-type variables go in the RAM? The references go on the stack,

while the objects themselves go on the heap.

13.What is the difference between the value-type variables and reference-type variables in

terms of garbage collection? The value-type variables are not garbage-collected, they just

fall off the stack when they fall out of scope, the reference-type objects are picked up by

GC when their references go null.


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14. How do you convert a string into an integer in .NET? Int32.Parse(string)

15. How do you box a primitive data type variable? Assign it to the object, pass an object.

16.Why do you need to box a primitive variable? To pass it by reference.

17.Whats the difference between Java and .NET garbage collectors? Sun left the

implementation of a specific garbage collector up to the JRE developer, so their

performance varies widely, depending on whose JRE youre using. Microsoft standardized

on their garbage collection.

18. How do you enforce garbage collection in .NET? System.GC.Collect();

19. Can you declare a C++ type destructor in C# like ~MyClass()? Yes, but whats the

point, since it will call Finalize(), and Finalize() has no guarantees when the memory will be

cleaned up, plus, it introduces additional load on the garbage collector.

20.Whats different about namespace declaration when comparing that to package

declaration in Java? No semicolon.

21.Whats the difference between const and readonly? You can initialize readonly

variables to some runtime values. Lets say your program uses current date and time as

one of the values that wont change. This way you declare public readonly string DateT =

new DateTime().ToString().

22.What does \a character do? On most systems, produces a rather annoying beep.

23. Can you create enumerated data types in C#? Yes.

24.Whats different about switch statements in C#? No fall-throughs allowed.


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25. What happens when you encounter a continue statement inside the for loop? The code

for the rest of the loop is ignored, the control is transferred back to the beginning of the

loop.

26. Is goto statement supported in C#? How about Java? Gotos are supported in C#to the

fullest. In Java goto is a reserved keyword that provides absolutely no functionality

C# Interview Questions | C Sharp Interview Questions

1) Explain about C#?

C # is also known as c sharp. It is a programming language introduced by Microsoft. C# contains

features similar to Java and C++. It is specially designed to work with Microsoft .NET platform.

2) Explain about the rules for naming classes in C#?These are the rules for naming classes in c sharp.

Must begin with a letter. This letter may be followed by a sequence of letters, digits (0-9), or_. The first character in a class name cannot be a digit.

Must not contain any embedded space or symbol like ? - + ! @ # % & * ( ) { } [ ] , : ; \ and/.However an underscore _ can be used wherever a space is required.

Must not use a keyword for a class name.

3) What are the rules to be followed while naming variables in C#.

The following rules are used for naming variables in C#.* Must begin with a letter or an underscore _ which may be followed by a sequence of letters,

digits (0-9), or _. The first character in a variable name cannot be a digit.* Must not contain any embedded space or symbol like ? - + ! @ # % & * ( ) { } [ ] , : ; \ and/.

However an underscore _ can be used wherever a space is required. Must be unique

Can have any number of characters Keywords cannot be used as variable names.

4) What are the different types ofData?

There are two different types of data supported by C#. They are

1) Value types: -They directly contain data. When you declare an int variable, the systemallocates memory to store the value.2) Reference type: -The reference types do not maintain data but they contain a reference to the

variables, which are stored in memory. This means that if the value in the memory location ismodified by one of the variables, the other variables automatically reflect the changes value

5) Explain about member functions?A function is a set of statements that perform a specific task in response to a message. The


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functions of a class are called member functions in Csharp. Member functions are declaredinside the class. The function declaration introduces the function in the class and the function

definition contains the function code.

6) Explain about comment entry?

Comments are a part of the program and are used to explain the code. Compilers ignorecomment entries. If a comment entry spans more than one line, it has to be enclosed within /*and */. The symbol // treats the rest of code within the same line as a comment.

7) What are operators?

Applications use operators to process the data entered by a user. Operators like + and are usedto process variables and return a value. An operator is a set of one or more characters that is used

for computations or comparisons. Operators can transform one or more data values, calledoperands into a new data value.

8) Explain about the break statement?

A break statement is used to exit the switch statement. This prevents the execution of theremaining case structures by ending the execut ion of the switch case construct. Each breakstatement terminates the enclosing switch statement and the flow of control. If none of the cases

match the default case is invoked.

9) Define encapsulation?Encapsulation literally means to enclose in or as if in a capsule. Encapsulation is defined as the

process of enclosing one or more items within a physical or logical package. It involvespreventing access to nonessential details.

10) Define access specifier with reference to class?

An access specifier defines the scope of a class member. A class member refers to the variablesand functions in a class. A program can have one or more classes. You may want some members

of a class to be accessible to other classes. But, you may not want some other members of theclass to be accessible outside the class.

11) Describe about private access specifier?

The private access specifier allows a class to hide its member variables and member functionsfrom other class objects and functions. Therefore, the private member of a class is not visible

outside a class. If a member is declared private, only the functions of that class can access themember. Even the instance of the class cannot access its members

12) Explain about protected internal access specifier?

This specifier allows a class to hide its member variables and member functions to be accessedfrom other class objects and functions, except the child class, within the application. The

protected internal access specifier becomes important while implementing inheritance.

13) Define parameter by value?

Pass by value is the default mechanism for passing parameters to a method. The simplest


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definition of a value parameter is a data type name followed by a variable name. When a methodis called, a new storage location is created for each value parameter. The values of the

corresponding expressions are copied into them. The expression supplied for each valueparameter must be similar to the declaration of the value parameter.

14) State the methods through which parameters can be passed?Parameters can be passed by using any one of the following mechanism.Value: -They are sometimes called in or out parameters; therefore, the data can be transferred

into the method but cannot be transferred out.Reference: -Are sometimes called in or out parameters, therefore, the data can be transferred into

the method and out again.Output: -Are sometimes called out parameters, data can be transferred out of the method.

15) Explain about reference parameter?

A reference parameter is a reference to a memory location of a data member. Unlike a valueparameter, a reference parameter does not create a new storage location. Instead a reference

parameter represents the same location in memory as the variable that is supplied in the methodcall.

16) How do you use a structure?A structure is a value type data type. When you want a single variable to hold related data of

various data types, you can create a structure. To create a structure you use the struct keyword.

17) What is an enumerator?Enumeration is a value data type, which means that enumeration contains its own values and

cannot inherit or pass inheritance. Enumerator allows you to assign symbolic names or integralconstants.

1. How many types of JIT compilers are available?There are Two types of JIT compilers.

standard JIT compiler.

EconoJIT compiler.

2.What are the different types of assemblies name them?

Private

Public/Shared


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Satellite assembly

3.What is GAC? What are the steps to be taken to pick up the latest version from

GAC?

This Global Assembly Cache(GAC) stores .NET assemblies to be shared by several

applications on that computer.publisher policy file is the configuration file to redirect to

different version

1. Create the publisherPolicy assembly using the assembly linker

2. Add the publisher policy assembly to the GAC using GACutil tool

Gacutil /i

3. During runtime CLR is looking into the publisher policy file and redirect the

application to bind with new version assembly as specified inside the publisher policy.

4.How do we use different versions of private assemblies in same application

without re-build?

In Asseblyinfo file need specify assembly version.

assembly: AssemblyVersion

5.Different methods of using a legacy COM component in .NET framework?

1. TLBIMP to create an Assembly from a COM component

2. Reference a COM component directly from .NET Editor

6.How do you implement SSL?

1. create certificate request

[

=>Right click on the website (VD)

=>ClickDirectory Security Tab and clickServer Certificate

=> Type name of certificate , Organization name , server name

location info,

=> Type the path need to save certificate information Submit certificate request.


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]

7.What is ref parameter?What is out parameter?

Ref Parameter:Used to pass a parameter as a reference so that the function called will

set the value. This could be used to return more than 1 value by a function.

e.g.

public int AddMuliply( int a , int b, ref int c)

{

c = a*b;

return ( a+b);

}

The above function, returns the addition of two numbers as well as computes the

multiplication result and passes to the calling function.

Out Parameter:Used to pass values from the aspx Code-behind to the aspx page.

The difference is that for a ref parameter, you have to assign a value before you call the

function, while for OUT parameter, you dont have to assign a value, the calling function

assumes that the called function would assign some value.

A ref parameter must first be initialized before being passed from the calling function to

the called function. but a out parameter need not be initialized, we can pass it directly

when we pass a parameter as ref to a method, the method refers to the same variable and

changes made will affect the actual variable.

even the variable passed as out parameter is same as ref parameter, but implementation in

c# is different, Arguement passed as ref parameter must be initialized before it is passed

to the method. But in case of out parameter it is not necessary. But after a call to a

method as out parameter it is necessary to initialize.

When to use out and ref parameter, out parameter is used when we want to return more

than one value from a method. Ref parameter can be used as both input and o/p parameter

out parameter can be used as only output parameter

8.What is boxing?What is the benefits and disadvantages?


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What is the top .NET class that everything is derived from?

System.Objects

What is an abstract class?

The abstract modifier can be used with classes, methods, properties, indexers, and events.

Use the abstract modifier in a class declaration to indicate that a class is intended only to be a

base class of other classes.

Abstract classes have the following features:

An abstract class cannot be instantiated.

An abstract class may contain abstract methods and accessors.

It is not possible to modify an abstract class with the sealed modifier, which means that the class

cannot be inherited.

A non-abstract class derived from an abstract class must include actual implementations of all

inherited abstract methods and accessors.

Use the abstract modifier in a method or property declaration to indicate that the method or

property does not contain implementation.

Abstract methods have the following features:

An abstract method is implicitly a virtual method.

Abstract method declarations are only permitted in abstract classes.

Because an abstract method declaration provides no actual implementation, there is no method

body; the method declaration simply ends with a semicolon and there are no braces ({ })

following the signature. For example:

public abstract void MyMethod();

________________________________________

abstract class is a prototype of a class. it is used to provide partial

class implementation. abstract class contain abstract method which can be implemented by

derived class.

some rules for abstract class are following-:

1) an object of an abstract class can never be created.


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2)you can not declare an abstract method outside the abstract class.

3)can not be declared sealed.

WHAT IS THE ADVANTAGE OF SERIALIZATION?

Serialization is the process of maintaing object in the form stream. it is useful in case of

remoting.

Serialization is the process of converting object into byte stream which is useful to transport

object(i.e remoting),persisting object(i.e files,database)

SERIALIZATION IS PROCESS OF LOADING THE OBJECT STATE IN THE FORM

OF BYTE STREAMS IN DATABASE/FILE SYATEM.

Can we inherit the java class in C# class,how?

Java Programming language is not supported with .Net Framework hence you cannot inherit

javaclass in C# class.Also Java has JavaByte code after compiling similar to MSIL which is

similar but cannot inherit due to framework support.

Are C# destructors the same as C++ destructors?

No. They look the same but they are very different. The C# destructor syntax (with the familiar ~

character) is just syntactic sugar for an override of the System.Object Finalize method. This

Finalize method is called by the garbage collector when it determines that an object is no longer

referenced, before it frees the memory associated with the object. So far this sounds like a C++

destructor. The difference is that the garbage collector makes no guarantees about when this

procedure happens. Indeed, the algorithm employed by the CLR garbage collector means that it

may be a long time after the application has finished with the object. This lack of certainty is

often termed non-deterministic finalization, and it means that C# destructors are not suitable for

releasing scarce resources such as database connections, file handles etc.

To achieve deterministic destruction, a class must offer a method to be used for the purpose. The

standard approach is for the class to implement the IDisposable interface. The user of the object

must call the Dispose() method when it has finished with the object. C# offers the using

construct to make this easier.


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What is wrapper class? is it available in c#?

Wrapper Classes are the classes that wrap up the primitive values in to a class that offer utility

method to access it . For eg you can store list of int values in a vector class and access the class.

Also the methods are static and hence you can use them without creating an instance . The values

are immutable .

wrapper class are those class in which we can not define and call all predefined function .it is

possible in java not C#.

Which tool is used to browse the classes, structs, interfaces etc. in the BCL?

wincv as in Windows Class View

How is the using() pattern useful?What is IDisposable? How does it support deterministic

finalization?

The using() pattern is useful because it ensures that Dispose() will always be called when a

disposable object (defined as one that implements IDisposable, and thus the Dispose() method)

goes out of scope, even if it does so by an exception being thrown, and thus that resources are

always released.

What happens when a C# project has more than 1 Main methods

f the project is compiled using /main switch with the compiler then the project compiles

successfully.

For example:

class A

{

public static void Main(string[] args)

{

Console.WriteLine("Main in class A");

}

}


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class B

{


{

Console.WriteLine("Main in class B");

}

}

Now compile with the /main switch with the C# compiler like

csc MultipleMain.cs /main:A

This will compile without error and while executing it will show Main in class A

Attempting to compile an application consisting of multiple classes with defined Main methods

and not specifying the /main switch will result in a compiler error.

How do you refer parent classes in C#? A) Super B) This C) Base

This keyword is used for reffering current object and Base keyword is used for referring parrent

class. so ans. is C.

Super: Super is used to Refer the Base Class in JAVA

This: This is used to Refer the Current or Child Class in C#

Base: Base is used to ReferThe Parent or Base Class

What is object pooling

Defination: A performance optimization based on using collections of pre-allocated resources,

such as objects or database connections

With the advent of the .NET platform, writing code that pools objects and threads has become a

simple task. By using the Threading and Collections namespaces, you can create robust object

pooling applications. This could also be done by implementing COM+ interop interfaces into

your code.

Which method is actually called ultimately when Console.WriteLine( ) is invoked?


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A) Append( )

B) AppendFormat( )

C) Tostring( )

Ans: B, AppendFormat() method is called.

What is an Assembly?

An assembly is a file that is automatically generated by the compiler upon successful

compilation of every .NET application. It can be either a Dynamic Link Library or an executable

file. It is generated only once for an application and upon each subsequent compilation the

assembly gets updated. The entire process will run in the background of your application; there is

no need for you to learn deeply about assemblies. However, a basic knowledge about this topic

will help you to understand the architecture behind a .NET application.

An assembly is used by the .NET CLR(Common Language Runtime) as the smallest unit for:

deployment; version control; security; type grouping and code reuse. Assemblies consists of a

manifest and one or more modules and/or files like HTML, XML, images, video clips,...

An assembly can be thought of as a logical DLL and must contain a single manifest and may

optionally contain type meta data, MSIL (Microsoft Intermediate Language) and resources.

Assemblies come in 2 flavors: application private and shared. Application private assemblies

are used by one application only. This is the default style of assembly. Such assemblies must

reside in the application folder.

Shared assemblies are meant to be used by more than one application. They must have a

globally unique name and must be defined in the GAC (Global Assembly Cache). To learn

more about viewing the GAC

Basically there are two kind of assemblies when it comes to deployment.

Private Assemblies

Shared Assemblies

Private assemblies are the ones which are in your application folder itself. They can be easily


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and uniquely identified by their name.

These type of assemblies can be deployed simply by copying them to the bin folder of your

application.

Shared Assemblies are those which can be shared by multiple applications on the machine.

For this we have to place the Shared assembly in the GAC.

Now since we can install any application or assembly created by any company, that is we install

assemblies from oracle, microsoft and similarly from many other companies.

There is always a possiblity that they may use the same assembly name as your assembly name.

If such type of assemblies are placed in the GAC then we cannot uniquely identify a particular

assembly.But if we give a strong name to the assmebly then it is like a unique identifier for the

assembly.It is Globally unique.

Strong name consists of

1. Name of the assembly

2. Public key token

3. optionally any resources

4. Version Number

So basically to uniquely identify a particular assembly from the GAC we have to give it a strong

name. Its that simple.

The Shared assembly can be deployed in to GAC by using the GACUTIL tool with the -i switch

gacutil -i assemblyname

or simply copying it to the assembly folder in the windows directory (XP) orWINNT

directory(others)

Also there are Satellite Assemblies which contian only resources like strings, images etc.

Also there are dynamic assemblies which are generated on the fly dynamically.


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What does the modifier protected internal in C# mean?

The Protected Internal can be accessed by Members of the Assembly or the inheriting class, and

of course, within the class itself.

In VB.NET, the equivalent of protected internal is protected friend.

The access of this modifier is limited to the current assembly or the types derived from the

defining class in the current assembly. To know more on different types of access specifiers

Can multiple data types be stored in System.Array?

So whats an array all about? An array is a collection of items of the same type, that is grouped

together and encompassed within an array object. The array object, or the System.Array object to

be precise, is derived from the System.Object class. It is thus, stored in the form of a heap in the

memory.

An array may be of single dimensional, multi-dimensional or jagged (a jagged array means an

array within an array).

A group of items when assigned values within braces implicitly derive from System.Array class.

See example below written in C#...

int[] testIntArray = new int[4] { 2, 3, 4, 5 };

Object[] testObjArray = new Object[5] { 32, 22, 23, 69, 75 };

Ideally an array should contain a single data type. But still in case there is a requirement to place

data of different data types in a specific array, then in such a scenario, the data elements should

be declared as an object type. When this is done, then each element may point ultimately to a

different data type. See code example below written in VB.NET...

Dim allTypes As Object() = New Object() {}

'In this kind of scenario, the performance may tend to slow down, as data conversions may take

place.

'In case a value type is converted to reference type, then boxing and unboxing occurs

'To know more on Value Types & Reference Types, Click Here


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Dim studentTable(2) As Object

studendTable(0) = "VishalKhanna"

studentTable(1) = 28

studentTable(2) = #9/1/1978#

'To get these values of these varying datatypes, their values are converted to their original data

type

Dim myAge As Integer = CInt(studentTable(1))

Dim myBirthDay as Date = CDate(studentTable(2))

How to sort array elements in descending order in C#?

Elements of an array may not be sorted by default. To sort them in descending order, the Sort()

method is first called. Next, to descend the order, call the Reverse() method

Whats the use of "throw" keyword in C#?

The throw keyword is used to throw an exception programatically in C#. In .NET, there is an in-

built technique to manage & throw exceptions. In C#, there are 3 keyword, that are used to

implement the Exception Handling. These are the try, catch and finally keywords. In case an

exception has to be implicitly thrown, then the throw keyword is used. See code example below,

for throwing an exception programatically...

class SomeClass

{

public static void Main()

{

try

{

throw new DivideByZeroException("Invalid Division Occured");

}

catch(DivideByZeroException e)


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Calc obj;

int Result;

Result = obj.fnMultiply(2,3,4); // The second fnMultiply would be called

Result = obj.fnMultiply(3,4); // The first fnMultiply would be called

//Here, the call depends on the number of parameters passed, polymorphism is achieved using

overloading

How to add a ReadOnly property in C#?

Property - A property is an entity that describes the features of an object. A property is a piece

of data contained within a class that has an exposed interface for reading/writing. Looking at that

definition, you might think you could declare a public variable in a class and call it a property.

While this assumption is somewhat valid, the true technical term for a public variable in a class

is a field. The key difference between a field and a property is in the inclusion of an interface.

We make use of Get and Set keywords while working with properties. We prefix the variables

used within this code block with an underscore. Value is a keyword, that holds the value which is

being retrieved or set. See code below to set a property as ReadOnly. If a property does not have

a set accessor, it becomes a ReadOnly property.

public class ClassA

{

private int length = 0;

public ClassA(int propVal)

{

length = propVal;

}

public int length

{

get

{

return length;

}


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}

}

How to prevent a class from being inherited? Sealed in C#?

In order to prevent a class in C# from being inherited, the sealed keyword is used. Thus a sealed

class may not serve as a base class of any other class. It is also obvious that a sealed class cannot

be an abstract class. Code below...

sealed class ClassA

{

public int x;

public int y;

}

No class can inherit from ClassA defined above. Instances of ClassA may be created and its

members may then be accessed, but nothing like the code below is possible...

class DerivedClass: ClassA {} // Error

Can we inherit multiple interfaces in C#?

Yes. Multiple interfaces may be inherited in C#.

Note that when a class and multiple interfaces are to be inherited, then the class name should be

written first, followed by the names of the interfaces. See code example below, on how to inherit

multiple interfaces in C#.

class someclass : parentclass, IInterface1, IInterface2

{

//...Some code in C#

}

What are the different ways of overloading methods in C#?

What is function overloading in C#?


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Before knowing the different methods of overloading in C#, lets first clear out what exactly

overloading is. Overloading is the OOPs concept of using a method or a class in different styles

by modifying the signature of the parameters in it. To know more on overloading, Click Here.

In order to achieve overloading, there may be several techniques applied. There are different

types of overloading like OperatorOverloading, Function Overloading etc.

Function overloading may be achieved by changing the order of parameters in a function, by

changing the types passed in the function, and also by changing the number of parameters passed

in a function. See code sample below to see types of overloading.

//Define a method below

public void fnProcess(int x, double y)

{

......

}

//change the order of parameters

public void fnProcess(double x, int y) {

//.......Some code in C#

}

//Similarly, we may change the number of parameters in fnProcess

//and alter its behaviour

How to call a specific base constructor in C#?

What is a Constructor? - It is a method that gets invoked when an instance of a class is created.

In case a class has plenty of constructors, i.e. there are plenty of overloaded constructors, in such

a scenario, it is still possible to invoke a specific base constructor. But there is a special way, as

explicit calls to a base constructor is not possible in C#. See code below:

public class dotnetClass

{

public dotnetClass()


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{

// The constructor method here

}

// Write the class members here

}

//Sample code below shows how to overload a constructor


{


{

// This constructor is without a parameter

// Constructor #1

}

public dotnetClass(string name)

{

// This constructor has 1 parameter.

// Constructor #2

}

}

This constructor gets executed when an object of this class is instantiated. This is possible in C#.

Calling a specific constructor will depend on how many parameters, and what parameters match

a specific constructor. Note that a compile time error may get generated when 2 constructors of

the same signature are created.

We may make use of the this keyword and invoke a constructor. See code example below.

this("some dotnet string");

//This will call Constructor #2 above


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What is the use of the base keyword.

Suppose we have a derived class named dotnetderivedclass. If this derived class is to invoke the

constructor of a base class, we make use of the base keyword. See code example below on how

to use a base keyword to invoke the base class constructor.


{


{

// The 1st base class constructor defined here

}

public dotnetClass(string Name)

{

// The 2nd base class constructor defined here

}

}

public class dotnetderivedclass : dotnetClass

// A class is being inherited out here

{

public dotnetderivedclass()

{

// dotnetderivedclass 1st constructor defined here

}

public dotnetderivedclass(string name):base(name)

{

// dotnetderivedclass 2nd constructor defined here

}

}


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Note that we have used the base keyword in the sample code above. The sequence of execution

of the constructors will be as follows:

public dotnetClass() method -> public dotnetderivedclass() method

The above sequence triggers when there is no initializer to the base class, and thus it triggers the

parameterless base class constructor. The other base class constructor may also get invoked when

we pass a parameter while defining it.

What is a static constructor?

Static Constructor - It is a special type of constructor, introduced with C#. It gets called before

the creation of the first object of a class(probably at the time of loading an assembly). See

example below.

Example:

public class SomeClass()

{

static SomeClass()

{

//Static members may be accessed from here

//Code for Initialization

}

}

While creating a static constructor, a few things need to be kept in mind:

* There is no access modifier require to define a static constructor

* There may be only one static constructor in a class

* The static constructor may not have any parameters

* This constructor may only access the static members of the class

* We may create more than one static constructor for a class

Can a class be created without a constructor?

No. In case we dont define the constructor, the class will access the no-argument constructor


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from its base class. The compiler will make this happen during compilation.

What are generics in C#?

Generics in C# is a new innovative feature through which classes and methods in C# may be

designed in such a way that the rules of a type are not followed until it is declared. The generics

feature in C# has been introduced with version 2.0 of the .NET Framework. Using generics, a

class template may be declared that may follow any type as required at runtime. The class

behavior is later governed by the type that we pass to the class. Once the type is passed, the class

behaves depending on the type passed to this generic class.

What is the use of the main() function in C#?

Every executable C# application must contain a class defining a Main() method that signifies the

entry point of the application. Note that the Main() method is of the access type public by nature.

Moreover, it is also static. See example below:

using System;

class Question

{

public static int Main(string[] args)

{

Console.Writeline("Another Question");

Console.Readline();

return 0;

}

}

A public member is accessible from other types. The main() method is set as static so that it may

be invoked at class level itself, without the need of creating an instance of it. The single

parameter is an array of strings. that may contain any number of incoming command line

arguments.


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Can we set the specifier of the main() method in C# as private?

Yes. When the access specifier is set as private for the Main() method, then other assemblies

may not invoke this class' Main() method as the starting point of the application. The startup

scope gets limited to the class in context itself. See code below:

private static void Main()

{

//This code isn't invoked automatically by other assemblies

}

Can we set different types of parameters & return-types in main() method"?

Yes. The Main() method may easily be played around with by developers by passing different

parameters and setting different return types. See the code below, that demonstrates different

ways the Main() method may be implemented:

(1)


{

//NO return type, the argument is an array of strings

}

(2)


{

//Return type is int, argument is an array of strings

}

(3)

public static int Main()

{

//Return type is int, NO arguments

}


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(4)


{

//Return type is void, NO arguments

}

What is the use of GetCommandLineArgs() method?

The GetCommandLineArgs() method is used to access the command line arguments. The return

value of this method is an array of strings. It is a method of the System.Environment class. See

the code example below:


{

string[] strArgs = System.Environment.GetCommandLineArgs();

Console.WriteLine("Arguments {0}", strArgs[0]);

}

What is the use of System.Environment class?

The class System.Environment is used to retrieve information about the operating system. Some

of the static members of this class are as follows:

1) Environment.OSVersion - Gets the version of the operating system

2) Environment.GetLogicalDrives() - method that returns the drives

3) Environment.Version - returns the .NET version running the application

4) Environment.MachineName - Gets name of the current machine

5) Environment.Newline - Gets the newline symbol for the environment

6) Environment.ProcessorCount - returns number of processors on current machine

7) Environment.SystemDirectory - returns complete path to the SystemDirectory

8) Environment.UserName - returns name of the entity that invoked the application

Why is the new keyword used for instantiating an object in .NET?

The new keyword instructs the .NET compiler to instantiate a new object, with appropriate

number of bytes (depending on the type) for the object and gather required memory from the


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managed heap.

What are the default values for bool, int, double, string, char, reference-type variables?

When the objects of the following types are declared, then they have a default value during

declaration. The following table shows the default value for each type:

TypeDefault Value

bool false

int 0

double 0

string null

char '\0'

Reference Type null

How to declare a constant variable in C#? What is the use of the const keyword?

If a variable needs to have a fixed value, that may not be changed across the application's life,

then it may be declared with the const keyword. The value assigned to a constant variable (using

the const keyword) must be known at the time of compilation

In C#, can we create an object of reference type using const keyword?

No. A constant member may not be created of an object that is of reference type, because its

value is decided dynamically at runtime.

What is the difference between const and readonly in C#?

When using the const keyword to set a constant variable, the value needs to be set at compile

time. The const keyword may not be used with an object of reference type.

In case a reference type needs to be assigned a non-changeable value, it may be set as readonly

What are the different parameter modifiers available in C#?

What is a parameter modifier?


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Parameter modifiers in C# are entities that controls the behaviour of the arguments passed in a

method. Following are the different parameter modifiers in C#:

1) None - if there is NO parameter modifier with an argument, it is passed by value, where the

method recieves a copy of the original data.

2) out - argument is passed by reference. The argument marked with "out" modifier needs to be

assigned a value within this function, otherwise a compiler error is returned.

public void multiply(int a, int b, out int prod)

{

prod = a * b;

}

Here, note that prod is assigned a value. If not done so, then a compile time error is returned.

3) params- This modifier gives the permission to set a variable number of identical datatype

arguments.

Note that a method may have only one "params" modifier. The params modifier needs to be in

the last argument.

static int totalruns(params int[] runs)

{

int score = 0;

for(int x=0; x

&nsbp;score+=runs[x];

return score;

}

Further, from the calling function, we may pass the scores of each batsman as below...

score = totalruns(12,36,0,5,83,25,26);

4) ref - The argument is given a value by the caller, where data is passed by reference. This value

may optionally be reset in the called method. Note that even if NO value is set in the called

method for the ref attribute, no compiler error is raised.

What is the difference between out and ref in C#?

1) out parameters return compiler error if they are not assigned a value in the method. Not such


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with ref parameters.

2) out parameters need not be initialized before passing to the method, whereas ref parameters

need to have an initial value before they are passed to a method.

What is delay signing?

Delay signing allows you to place a shared assembly in the GAC by signing the assembly with

just the public key. This allows the assembly to be signed with the private key at a later stage,

when the development process is complete and the component or assembly is ready to be

deployed. This process enables developers to work with shared assemblies as if they were

strongly named, and it secures the private key of the signature from being accessed at different

stages of development.

Is there an equivalent of exit() for quitting a C# .NET application?

Yes, you can use System.Environment.Exit(int exitCode) to exit the application or

Application.Exit() if it's a Windows Forms app.

Can you prevent your class from being inherited and becoming a base class for some other

classes?

Yes, that is what keyword sealed in the class definition is for. The developer trying to derive

from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It

is the same concept as final class in Java.

If a base class has a bunch of overloaded constructors, and an inherited class has another

bunch of overloaded constructors, can you enforce a call from an inherited constructor to

an arbitrary base constructor?

Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate

constructor) in the overloaded constructor definition inside the inherited class.

I was trying to use an "out int" parameter in one of my functions. How should I declare the

variable that I am passing to it?


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You should declare the variable as an int, but when you pass it in you must specify it as 'out', like

the following:

int i;

foo(out i);

where foo is declared as follows:

[return-type] foo(out int o) { }

How do I make a DLL in C#?

You need to use the /target:library compiler option.

Is XML case-sensitive?

Yes, so and are different elements.

How do I simulate optional parameters to COM calls?

You must use the Missing class and pass Missing.Value (in System.Reflection) for any values

that have optional parameters.

Will finally block get executed if the exception had not occurred?

Yes.

What is the C# equivalent of C++ catch (), which was a catch-all statement for any

possible exception? Does C# support try-catch-finally blocks?

Yes. Try-catch-finally blocks are supported by the C# compiler. Here's an example of a try-

catch-finally block:

using System;

public class TryTest

{

static void Main()

{

try

{


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Console.WriteLine("In Try block");

throw new ArgumentException();

}

catch(ArgumentException n1)

{

Console.WriteLine("Catch Block");

}

finally

{

Console.WriteLine("Finally Block");

}

}

}

Output: In Try Block

Catch Block

Finally Block

IfI return out of a try/finally in C#, does the code in the finally-clause run? Yes. The code in the

finally always runs. If you return out of the try block, or even if you do a "goto" out of the try,

the finally block always runs, as shown in the following

example:

using System;

class main

{


{

try

{

Console.WriteLine("In Try block");

return;

}


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finally

{

Console.WriteLine("In Finally block");

}

}

}

Both "In Try block" and "In Finally block" will be displayed. Whether the return is in the try

block or after the try-finally block, performance is not affected either way. The compiler treats it

as if the return were outside the try block anyway. If it's a return without an expression (as it is

above), the IL emitted is identical whether the return is inside or outside of the try. If the return

has an expression, there's an extra store/load of the value of the expression (since it has to be

computed within the try block).

Is there a way to force garbage collection?

Yes. Set all references to null and then call System.GC.Collect(). If you need to have some

objects destructed, and System.GC.Collect() doesn't seem to be doing it for you, you can force

finalizers to be run by setting all the references to the object to null and then calling

System.GC.RunFinalizers().

Is there regular expression (regex) support available to C# developers?

Yes. The .NET class libraries provide support for regular expressions. Look at the documentation

for the System.Text.RegularExpressions namespace.

Does C# support properties of array types?

Yes. Here's a simple example: using System;

class Class1

{

private string[] MyField;

public string[] MyProperty

{


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get { return MyField; }

set { MyField = value; }

}

}

class MainClass

{


{

Class1 c = new Class1();

string[] arr = new string[] {"apple", "banana"};

c.MyProperty = arr;

Console.WriteLine(c.MyProperty[0]); // "apple"

return 0;

}

}

What connections does Microsoft SQL Server support?

Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft

SQL Server username and passwords)

When do you absolutely have to declare a class as abstract (as opposed to free-willed

educated choice or decision based on UML diagram)?

When at least one of the methods in the class is abstract. When the class itself is inherited from

an abstract class, but not all base abstract methods have been over-ridden.

Why would you use untrusted verification?

Web Services might use it, as well as non-Windows applications.

How is method overriding different from overloading?

When overriding, you change the method behavior for a derived class. Overloading simply

involves having a method with the same name within the class.


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What is the implicit name of the parameter that gets passed into the class set method?

Value, and its datatype depends on whatever variable we are changing.

How do I register my code for use by classic COM clients?

Use the regasm.exe utility to generate a type library (if needed) and the necessary entries in the

Windows Registry to make a class available to classic COM clients. Once a class is registered in

the Windows Registry with regasm.exe, a COM client can use the class as though it were a COM

class

Q1.What isWPF?

WPF stands forWindows Presentation Foundation. It is an application programming Interface

for developing rich UI on Windows. WPF is introduced in .NET 3.0. By the use ofWPF we can

create two and three dimensional graphics,animations etc.

Q2.Wh

at is XAML andh

ow it is related toW

PF?XAML is a new mark up language which is used for defining UI elements and its relationships

with otherUI elements. The XAML is introduced by WPF in .NET 3.0 WPF uses XAML forUI

design.

Q3. Does XAML file compiled or Parsed?

By default XAML files are compiled ,But we do have options to let it be parsed.

Q4.What is the root namespace used for Animations and 3D rendering in WPF?

System.Windows.Media namespace.

Q5.What are the names of main asseblies used by WPF?


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a)WindowsBase

b)PresentationCore

c)PresentationFoundation

Q6.What operating systems support WPF?

Following are the operating systems that supportWPF

a)Windows7

b)Windows Vista

c)Windows XPService Pack 2 or later

Q7. Describe the types of documents supported by WPF?

There are two kinds of document supported by WPF

a)Flow format:Flow format document adjusts as per screen size and resolution

b)Fixed Format:Fixed Format document does not adjust as per screen size and resolution

Q8.What namespaces are needed to host aWPF control in Windows form application?

The following namespaces needs to be referenced :

a)PresentationCore.dll

b)PresentationFramework.dll

c)UIAutomationProvider.dll

d)UIAutomationTypes.dll

e)WindowsBase.dll

Q9.What is Dependency Property In WPF?

Windows Presentation Foundation (WPF) has a set of services that is used to extend the

functionality of a common language runtime property. These services are referred as the WPFproperty system. A property that is backed by the WPF property system is known as a

dependency property

Q10.What is routed event in WPF?


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A WPF user interface is constructed in a layered approach, where one visual element can have

zero or more child elements. so we can visualise the elements tree for the full page. Routed

events are a new feature provided by WPF which allows events to travel down the elements tree

to the target element, or bubble up the elements tree to the root element. When an event is raised,

it "travels" up or down the elements tree invoking handlers for that event on any element

subscribed to that event it encounters en route.This tree traversal does not cover the entire

elements tree, only the ancestral element chain between the root element and the element which

is the target of the event.

Interview Questions and Answer on .Net,C#,ASP.NET,SQL Server

y All .NET training videos and explanation are not just theory and one liners. They are in depthvideos with source code and explanation and finally taking out the actual meat which you need

to speak before the interviewer to impress him.

y We do not just provide videos and leave the developers on their own.Online support via livemeeting from Microsoft MVP's takes this product to a greater height.

y We understand no one can see 500 videos at one go. We organize regularC# training on varioustopics so that your learning curve is reduced to a great extent.

y Around 500 videos covering right from .NET, CSharp InterviewQuestions and Answers. Youare either a fresher /senior architect /project manager this solution is for every level.

y Full DVD delivered to your doorsteps( only forUSA , India and Canada).y Mock interviews, Mock interviews , Mock interviews and Mock interviews makes this solution

and perfect package for your job search. These mock interviews are conducted by our specialist

to evaluate how much you are prepared and ready.

y Superb one liner interview answer cheat sheet to make you revise in a day.y Videos are not just theory and talks , its Step by Step demonstration with actual code and

fundamentals.

y Money back if you are not satisfied with our videos and support.

Summary of Topics Covered in .Net Training


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We understand that working on a project is one thing but clearing interviews needs a change of

mind set and this solution is especially meant for the same. From the same aspect we have

divided our interview videos are divided in 5 essential categories :-

y Basic .NET, ASP.NET, OOPS and SQL Server. Interview questions and answersy New technologiesWCF,WPF, Silverlight , LINQ, Azure, EF and 4.0. Interview questions

and answers

y Design pattern, UML, Architecture, Estimation, Project management, VSTS. Interviewquestions and answers

y Complete Invoicing project end to end. Interview questions and answersy Server products (Sharepoint 2007 questions and answer videos). Interview questions and

answersy Best practices and SQL performance tuning. Interview questions and answers

Details of the above .Net Training Topics

Below is our detail video list of the above main .Net Training topics. All .net training videos go

in-depth with source code and then explaining you the one liner which you need to speak in the

interview.

Basic .NET, ASP.NET, OOPS and SQL Server Interview questions and answers.

y What is IL code, CLR, CTS, GAC & GC?y How can we do Assembly versioning?y can you explain how ASP.NET application life cycle and page life cycle events fire?y What is the problem with Functional Programming?y Can you define OOP and the 4 principles of OOP?y What are Classes and Objects?y What is Inheritance?y What is Polymorphism, overloading, overriding and virtual?y Can you explain encapsulation and abstraction?y What is an abstract class?


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y What are various ways of hosting WCF service?y What is the difference of hosting a WCF service on IIS and Self hosting?y What is the difference between BasicHttpBinding and WsHttpBinding?y How can we do debugging and tracing in WCF?y Can you explain transactions in WCF (theory)?y How can we self host WCF service ?y What are the different ways of implementing WCF Security?y How can we implement SSL security on WCF(Transport Security)?y How can we implement transport security plus message security in WCF ?y How can we do WCF instancing ?y How Can we do WCF Concurency and throttling?y Can you explain the architecture ofSilverlight ?y What are the basic things needed to make a silverlight application ?y How can we do transformations in SilverLight ?y Can you explain animation fundamentals in SilverLight?y What are the different layout methodologies in SilverLight?y Can you explain one way , two way and one time bindings?y How can we consume WCF service in SilverLight?y How can we connect databases using SilverLight?y What is LINQ and can you explain same with example?y Can you explain a simple example of LINQ to SQL?y How can we define relationships using LINQ to SQL?y How can we optimize LINQ relationships queries using DataLoadOptions?y Can we see a simple example of how we can do CRUD using LINQ to SQL?y How can we call a stored procedure using LINQ?y What is the need ofWPF when we had GDI, GDI+ and DirectX?y Can you explain how we can make a simple WPF application?y Can you explain the three rendering modes i.e. Tier 0 , Tier 1 and Tier 2?y Can you explain the Architecture ofWPF?y What is Azure?y Can you explain Azure Costing?


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y Can we see a simple Azure sample program?y What are the different steps to create a simple Worker application?y Can we understand Blobs in steps, Tables & Queues ?y Can we see a simple example for Azure tables?y What is Package and One click deploy(Deployment Part - 1) ?y What is Web.config transformation (Deployment Part-2)?y What is MEF and how can we implement the same?y How is MEF different from DIIOC?y Can you show us a simple implementation of MEF in Silverlight ?

ASP .NET

1) Explain about ASP.NET?Microsoft introduced the .Net framework with the intention of bridging the gap ininteroperability between applications. This framework aims at integrating various programming

languages and services. The .NET offers a complete suite for developing and deployingapplications.

2) State the various features present in .NET?

It is designed to make significant improvements in code reuse, code specialization, resourcemanagement, Multilanguage development, security, deployment and administration. There arelots more features included in Microsoft .net which can be realized to a maximum potential with

the language support.3) Explain about .Net products?

Microsoft has already introduced visual studio.NET, which is a tool for developing .NETapplications by using programming languages such as Visual Basic, Visual C#, and Visual C++.

These products aim at allowing developers to create applications, which are capable ofinteracting seamlessly with each other.

4) Which platform does Microsoft .NET uses for exchanging data between applications?.Net products use eXtensible markup language (XML) for describing and exchanging data

between applications. It is a platform independent markup language. It allows computers to storedata in a format, which can be interpreted by any other computer system. XML can be used to

transfer structures data between heterogeneous systems.5) Explain about .NET services?

.NET helps you to create software as web services. A web services is an application or businesslogic that is accessible through standard internet protocols such as HTTP and simple object

access protocol. Users can subscribe to such a service and use it as long as they need it,regardless of the hardware and software platform.


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6) Explain about .NET framework?It is the foundation on which you design, develop and deploy applications. It is consistent and

simplified programming model that helps you to easily build robust applications. It forms thecore of the .NET infrastructure because it exists as a layer between the .NET applications and the

underlying operating system.

7) Explain about the Common language Runtime?The CLR is one of the most essential components of the .NET framework. CLR is theenvironment where all programs using .NET technologies are executed. It provides services such

as code compilation, memory allocation, and garbage collection. It translates the code intoIntermediate language which helps interoperability of code.

8) Explain about CLS?CLS consists of a set of common rules followed by all the languages of the .NET framework.

This set of rules is known as Common language specifications. CLS enables an object orapplication to interact with the objects or applications of other languages.

9) Explain about CTS?One of the specifications defined in CLS is common type system (CTs), which provides a type

system that is common across all languages. CTS define how data types are declared, used andmanaged in the code at run time. The size of integer and long variables is the same across all CLs

compliant programming languages.10) Explain the process of compilation in .NET?

When you compile a program in .NET, the conversion of source code to machine languagehappens in two stages. In the first stage, the compiler translates code into an IL instead of

machine language or assembly language. In the second stage the conversion ofIL to machinelanguage is done at run time by the JIt compiler.

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