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1: What
is IL?
(IL)Intermediate Language is also known as MSIL (Microsoft
Intermediate Language) or CIL (Common Intermediate Language). All .NET source
code is compiled to IL. This IL is then converted to machine code at the point
where the software is installed, or at run-time by a Just-In-Time (JIT)
compiler.
2: What
is the CLR?
Full form of CLR is Common Language Runtime and it forms the
heart of the .NET framework. All Languages have runtime and it’s the
responsibility of the runtime to take care of the code execution of the
program. IL (Intermediate language)-to-native translators and optimizer’s:- CLR
uses JIT and compiles the IL code to machine code and then executes. CLR also determines
depending on platform what is optimized way of running the IL code.
3: What
is the CTS?
In order that two languages communicate smoothly CLR has CTS
(Common Type System). Example in VB you have “Integer” and in C++ you have “long”
these data types are not compatible so the interfacing between them is very
complicated. In order that two different languages can communicate Microsoft introduced Common Type System. So
“Integer” data type in VB6 and “int” data type in C++ will convert it to
System.int32 which is data type of CTS.
4: What
is CLS (Common Language Specification)?
Microsoft has defined CLS which are nothing but guidelines
that language to follow so that it can communicate with other .NET languages in
a seamless manner.
5: What is Assembly?
Assembly is unit of deployment like EXE or a DLL.
An assembly consists of one or more files (dlls, exe’s, html
files etc.), and represents a group of resources, type definitions, and
implementations of those types. An assembly may also contain references to
other assemblies. These resources, types and references are described in a block
of data called a manifest. The manifest is part of the assembly, thus making
the assembly self-describing.
6: What is Namespace?
The namespace keyword is used to declare a scope.
This namespace scope lets you organize code and gives you a way to create
globally unique types.
Namespace logically group types. Example System.Web.UI
logically groups our UI related features. In Object Oriented world May times it’s
possible that programmers will use the same class name. By qualifying namespace
with class name this collision can be removed.
7: What
is garbage collection?
Garbage collection is a CLR feature which automatically manages
memory. Programmers forget to release the objects while coding. Laziness (Remember
in VB6 where one of the good practices is to set object to nothing). CLR
automatically releases objects when they are no longer referenced and in use.
8: What
are Value types and Reference types?
C# has two
varieties of data types: value and reference. When a variable is declared using
one of the basic, built-in data types or a user defined structure, it is a
value type. An exception is the string data
type, which is a reference type.
A data type is
a value
type if it holds the
data within its own memory allocation. Value types include the following: (All
numeric data types, Boolean, Char,
and Date, All structures, even
if their members are reference types)
A reference
type contains a
pointer to another memory location that holds the data. Reference types include
the following: (String, All arrays, even if
their elements are value types, Class types, such as Form, Delegates).
9: What
is concept of boxing and unboxing?
Boxing
|
Unboxing
|
|
Definition:
|
Boxing is the
process of converting a value type to the reference type.
(value
type to the type object)
|
Unboxing is the
process of converting
a
reference type to value type
|
Type
of Conversion:
|
Implicit
Conversion
|
Explicit
Conversion
|
Example:
|
int
i = 221;
object
obj = i; //boxing
|
object obj = 213;
i = (int)obj ; // unboxing
|
10: What’s
difference between VB.NET and C#.NET?
11:
What are exceptions? (Try,
Catch, Finally, Throw)
12: What is a Thread?
A thread is the basic unit to which the operating
system allocates processor time. Threading enables your Visual
Basic or C# program to perform concurrent processing so that you can do more
than one operation at a time. For example, you can use threading to monitor
input from the user, perform background tasks, and handle simultaneous streams
of input.
Threading solves problems with throughput and responsiveness,
but it can also introduce resource-sharing issues such as deadlocks and race
conditions.
Threads have the following properties:
·
Threads enable
your program to perform concurrent processing.
·
Threads share
the application's resources.
13: What
is Multi-threading?
Multi-threading forms subset of Multi-tasking instead of
having to switch between programs this feature switches between different parts
of the same program. Example you are writing in word and at the same time word
is doing a spell check in background.
14: Which namespace has threading? (Systems.Threading)
15: Can you explain in brief how can we
implement threading?
16:
What is a Web Service?
Web Services are business logic components which provide
functionality via the Internet using standard protocols such as HTTP. Web
Services uses Simple Object Access Protocol (SOAP) in order to expose the
business functionality. SOAP defines a standardized format in XML which can be
exchanged between two entities over standard protocols such as HTTP.
17: What
is the extension of web service and how to call a web service?
Extension: .asmx
To
call a Web service programmatically
·
Use the Web
reference name (or server name) as the namespace, and the name of its .WSDL
file (or the service name) as the proxy class.
18:
What’s a Class?
A class describes all the attributes of objects of that class,
as well as the methods that implement the behavior of member objects. It’s a
comprehensive data type which represent a blue print of objects. It’s a template
of object.
19: What’s
an Object?
It’s a basic unit of a system. An object is an entity that
has attributes, behavior, and identity. Objects are members of a class, and the
attributes and behavior of an object are defined by the class definition.
20: Abstraction?
It allows complex real world to be represented in simplified
manner. Example color is abstracted to RGB. By just making the combination of
these three colors we can achieve any color in world. It’s a model of real
world or concept.
21: Encapsulation?
The process of hiding all the internal details of an object
from the outside world.
22: What
is Association?
This is the simplest
relationship between objects. Example every customer has sales. So Customer
object and sales object have an association relation between them. Computer
uses keyboard as input device. Employee uses Bus Service for transportation. (Class A uses Class B.)
23: What
is Aggregation & Composition?
The main difference between an aggregation
and a composition is the property of your "has-a" relationship. The
aggregation “has-a" relationship is of "weak-type". Example in order to
make a “Accounts” class it has use other objects example “Voucher”, “Journal”
and “Cash” objects. So accounts class is aggregation of these three objects. (Class A is owns Class B). The composition "has-a" relationship of
"strong-type”.
Example
Body
consists of Arm, Head, and Legs. (Class A contains Class B).
24: What
is Inheritance?
Hierarchy is used to define more specialized classes based
on a preexisting generalized class. Example we have VEHICLE class and we can
inherit this class make more specialized class like CAR, which will add new
attributes and use some existing qualities of the parent class. Its shows more
of a parent-child relationship. This kind of hierarchy is called inheritance.
25: What
is Polymorphism?
When inheritance is used to extend a generalized class to a
more specialized class, it includes behavior of the top class (Generalized
class).The inheriting class often implement a behavior that can be somewhat
different than the generalized class, but the name if the behavior can be same.
It is important that a given instance of an object use the correct behavior, and
the property of polymorphism allows this to happen automatically.
26: What are Access
Specifiers and why we use?
Private
Protected
Public
27: Can
we create private constructor & use of private constructor ?
Yes. A private constructor is a special instance constructor. It is generally used in classes that contain static members only. The declaration of the empty constructor prevents the automatic generation of a default constructor. Private constructors are used to prevent creating instances of a class when there are no instance fields or methods, such as the Math class, or when a method is called to obtain an instance of a class.
class Sample
{
// Private Constructor:
private Sample() { }
public static double e = Math.E; //2.71828...
}
28: Can
constructor inherit?
Constructors
are not inherited. They are
called implicitly or explicitly by the child
constructor. The compiler creates a default constructor (one with no arguments) and a default copy constructor (one
with an argument which is a reference to
the same type). But if you want a constructor that will accept an int,
you have to define it explicitly.
class A
{
public:
explicit A(int x) {}
};
class B: public A
{
public:
explicit B(int x) : A(x) { }
};
29: What
is function overloading and overriding?
Function
overloading is same name
function but different arguments. Function over
riding means same name function and same as arguments.
30:
What are abstract classes?
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. You declare a pure virtual function by using a pure specifier (= 0) in the declaration
of a virtual member function in the class declaration.
31:
What’s an Interface?
An interface
contains only the signatures of methods, properties, events or indexers. A class or struct that implements the interface must
implement the members of the interface that are specified in the interface
definition.
32: What
is difference between abstract classes and interfaces?
OOPs interface vs abstract class
Interface
|
Abstract class
|
Interface support
multiple inheritance
|
Abstract class does not support multiple
inheritance
|
Interface doesn’t
Contains Data Member
|
Abstract class contains Data Member
|
Interface doesn’t
contains Constructors
|
Abstract class contains Constructors
|
An interface Contains
only incomplete member (signature of member)
|
An abstract class Contains both incomplete (abstract)
and complete member
|
An interface
cannot have access modifiers by
default everything is assumed as public
|
An abstract class can contain access modifiers for the subs, functions,
properties
|
Member of
interface cannot be Static
|
Only Complete
Member of abstract class can be Static
|
33: Difference between Virtual / Abstract
methods?
Virtual methods have an implementation and
provide the derived classes with the option of overriding it. Abstract methods
do not provide an implementation and forces the derived classes to override the method.
Abstract
|
Virtual
|
No Keyword
|
|
Can have
implementation?
|
No
|
Yes
|
Yes
|
Can override?
|
Must
|
Can but not a must
|
You can declare a
new method with the same name
|
Which keyword to use
to provide new implementation in the concrete class?
|
override
|
override
|
No keyword needed
|
If an object is
created of the base class type, which method will be executed?
|
Concrete
implementation
|
The parent
implementation will be called only if no implementation is provided in the
concrete class
|
Parent
implementation
|
If an object is
created of the concrete class type, which method will be executed?
|
Concrete
implementation
|
Concrete
implementation
|
The parent
implementation will be called only if no implementation is provided in the
concrete class
|
34: Difference between Classes and Structs?
The struct default access type is public. A struct
should typically be used for grouping data. The class default access type is
private, and the default mode for inheritance is private. A class should
be used for grouping data and methods that operate on that data. In short, the
convention is to use struct when the purpose is to group data, and use classes
when we require data abstraction and, perhaps inheritance. (instances of classes) may be
passed by reference and structures may be passed by value. Technically there
are only two differences between classes and structures: classes are declared
using the keyword class while structures are declared using
the keyword struct.
35: What is Static Variables?
A variable that
retains the same data throughout the execution of a program. In contrast, a dynamic variable can
have different values during the course of a program.
36: What is Waterfall Model?
37: What
is a delegate?
Delegate is a class that can hold a reference to a method or
a function. Delegate class has a signature and it can only reference those
methods whose signature is compliant with the class. Delegates are type-safe
functions pointers or callbacks.
38:
What are events?
As compares to delegates event works with source and listener
methodology. So listeners who are interested in receiving some events they
subscribe to the source. Once this subscription is done the source raises
events to all of its listener when needed. One source can have multiple
listeners.
39: Do
events have return type?
No events do not have return type.
40:
What does virtual keyword mean?
That method and property can be overridden.
41:
What is ENUM?
It’s used to define constants.
42: What is Array List?
43:
What are queues and stacks?
Queue is for first-in, first-out (FIFO) structures. Stack is
for last-in, first-out (LIFO) structures.
44: What
are static classes and variables and why we use?
A static class is basically the same as a
non-static class, but there is one difference: a static class cannot be
instantiated. In other words, you cannot use the new keyword
to create a variable of the class type. Because there is no instance variable,
you access the members of a static class by using the class name itself.
45: What
is dataset?
Dataset is a collection of Data Tables.
We use the Dataset type to store many Data Tables in a single collection.
Conceptually, the Dataset acts as a set of Data Table instances. This
simplifies programs that use many Data Tables.
46: What
are the types of dataset?
There are 2 types of dataset available.
1.
Strongly Typed DataSets
2.
Annotating Typed DataSets
47: What is MVC pattern?
The main purpose using MVC pattern is to decouple the GUI
from the Data. It also gives the ability to provide multiple views for the same
Data. MVC pattern separates objects in to three important sections:-
Model:
-
This section is specially for maintaining data. It is actually where your business
logic, querying database, database connection etc. is actually implemented.
Views:
-
Displaying all or some portion of data, or probably different view of data.
View is responsible for look and feel, Sorting, formatting etc.
Controller:
-
They are event handling section which affects either the model or the view.
Controller responds to the mouse or keyboard input to command model and view to
change. Controllers are associated with views. User interaction triggers the
events to change the model, which in turn calls some methods of model to update
its state to notify other registered views to refresh their display.
48: What
is ADO.NET?
Microsoft ActiveX® Data Objects (ADO). ADO.NET is an object-oriented set of
libraries that allows you to interact with data sources. Commonly, the
data source is a database, but it could also be
a text file, an Excel spreadsheet, or an XML file. ADO.NET defines
Dataset and Data Table objects which are optimized for moving disconnected
sets of data across intranets and Internets, including through firewalls.
49: What
is normalization?
50: What
is transitive dependency?
51: How
to select data from database using ado.net? Write code
52: How
to insert and update data from database using ado.net?
53:
What is connection string?
The connection string contains the information that the provider needs to
know to be able to establish a connection to the database or the data file.
56: Different
Data Access Technologies in .NET?
v ADO.NET
v ADO
v OLE DB.
57: What are indexers in c# (Types of indexes)?
Indexers
allow instances of a class or struct
to be indexed just like arrays. Indexers resemble properties except that their accessors take parameters.
Types of Indexes:-
1)
Clustered Index (CI)
2)
Non-Clustered Index (NCI)
3)
Covering Index
4)
Unique Index
58: Difference between Primary key and unique
key?
Primary Key:
i) Can be only one in a table
ii) It never allows null values
iii) Primary Key is unique key identifier and cannot be null and
must be unique.
Unique Key:
i) Can be more than one unique key in one table.
ii) Unique key can have null values.
iii) It can’t be candidate key.
iv) Unique key can be null and may not be unique.
60: What is the difference
between
char, nchar, varchar,
and nvarchar in SQL Server?
·
nchar and nvarchar can store Unicode characters.
·
char and varchar cannot store Unicode characters.
·
char and nchar are fixed-length which
will reserve storage space for number of characters you
specify even if you don't use up all that space.
·
varchar and nvarchar are variable-length which
will only use up spaces for the characters you store. It will not reserve storage like char or nchar.
·
nchar and nvarchar will take up twice
as much storage space, so it may be wise to use them only if you need Unicode
support.
61: What is thread, background thread and
foreground thread?
62: Why
anonymous types are better than tuples?
63: What is the difference between
convert.tostring and tostring ()?
Convert.ToString can handle
null value. Object.ToString() will throw an error if the object is null. So its
alway best to use Convert.Tostring() when you are converting reference type to
string. Value type cannot be null so you can use .ToString() for value types.
64: What is circular dependency?
65: What is the difference between Service
and Component?
A service can be made up of several components. Usually a service
provides one complete feature that is made up by combining different
components.
The service's user don't need to know anything about the
underlying components. User will deal only directly with the service while
service internally will be interacting with the components.
69: What are Generics?
Generics allow you to delay the specification of the data
type of programming elements in a class or a method, until it is actually used
in the program. In other words, generics allow you to write a class or method
that can work with any data type.
70: Response. Redirect (False vs True)?
71: Prove that only 1 instance of the object
is created for static classes?
72: What
is Difference between == VS .Equals ()?
The
equals ( ) method and the == operator perform two different
operations. The equals ( )
method compares the characters inside a String object. The == operator
compares two object references to see whether they refer to the same instance.
The following program shows how two different String objects can contain the
same characters, but references to these objects will not compare as equal.
75: What is the use of checked and unchecked
keyword?
C#
statements can execute in either checked or unchecked context. In a checked
context, arithmetic overflow raises an exception. In an unchecked context,
arithmetic overflow is ignored and the result is truncated.
78: Flow of web application in asp.net?
1:Page request.
2:Start
3: Initialization
4:Load
5: validation
6:Event handling
7:Rendering
8:Unload
79: Difference b/w
primary and unique key?
Primary
Key
|
Unique Key
|
v
Primary key does not accept null values.
v
There is only one primary key in a table.
v
Clustered index is created in Primary key.
v
Primary key allows each row in a table to be
uniquely identified and ensures that no duplicate rows exist.
|
v
Using Unique key, Null values are accepted.
v
More than one unique key can be defined
there in a table.
v
Non-Clustered index is created in unique key.
v
Unique key constraint is used to avoid the
duplication of key values within the rows of a table.
|
80: Difference b/w primary & foreign key?
Primary
Key
|
Foreign Key
|
v Primary key uniquely identify a record in the table.
v Primary Key can't accept null values.
v By default, Primary key is clustered index and data in
the database table is physically organized in the sequence of clustered
index.
v We can have only one Primary key in a table.
|
v Foreign key is a field in the table that is primary key
in another table.
v Foreign
key can accept multiple null value.
v Foreign key do not automatically create an index,
clustered or non-clustered. You can manually create an index on foreign key.
v We
can have more than one foreign key in a table.
|
80: what is Get ()
and Post ()?
POST METHOD: The POST method generates a FORM collection, which is
sent as a HTTP request body. All the values typed in the form will be stored in
the FORM collection.
GET METHOD: The GET method sends information by appending it to
the URL (with a question mark) and stored as A Query string collection. The
Query string collection is passed to the server as name/value pair. The length
of the URL should be less than 255 characters.
An HTTP GET is a request from the client to the server, asking for a resource.
An HTTP POST is an upload of data (form information, image data, whatever) from the client to the server.
81: What are joins?
Joins are use in database to get the data from multiple table of database.
There are many types of joins.
1:Inner join
2:Outer join
3:Self join
82: What is Managed
Code & Unmanaged Code?
Managed code is not compiled to machine code but to an intermediate
language which is interpreted and executed by some service on a machine and is
therefore operating within a (hopefully!) secure framework which handles
dangerous things like memory and threads for you. In modern usage this
frequently means .NET but does not have to.
Unmanaged code is compiled to machine code and therefore executed by
the OS directly. It therefore has the ability to do damaging/powerful things
Managed code does not. This is how everything used to work, so typically it's
associated with old stuff like .dlls
Native code is often synonymous with Unmanaged, but is not
identical.
83: what is Asp.net Session
& View state?
84: Difference String and String Builder (important)?
String
|
String
builder
|
v
It’s a class used
to handle strings.
v
Here concatenation
is used to combine two strings.
v
String object is
used to concatenate two strings.
v
The first string is combined to the
other string by creating a new copy in
the memory as a string object, and then the old string is deleted
v
Strings are immutable.
v system. String is non-updatable.
v
Slower
|
v
This is also the
class used to handle strings.
v
Here Append method
is used.
v
Here,
Stringbuilder object is used.
v
Insertion is done
on the existing string.
v
Usage of
StringBuilder is more efficient in case large amounts of
string manipulations have to be
performed.
v
system.stringbuilder is updatable.
v
String builder is faster than the string object.
v
String builder is mutable means we can able to re size the
memory size
|
85: Difference b/w sql server and Oracle?
86: What are the differences
between pointer variable and reference variable in C++?
A pointer can be re-assigned any number of times while a
reference can not be re-seated after binding.
Pointers can point nowhere (NULL), whereas reference always
refer to an object.
You can't take the address of a reference like you can with
pointers.
There's no "reference arithmetics" (but you can
take the address of an object pointed by a reference and do pointer arithmetics
on it as in &obj + 5)
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