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What is concept of Boxing and Unboxing ?

Posted By :Shashi Ray     Posted Date :March 05, 2009    Points :10   Category :ADO.Net 
Boxing permits any value type to be implicitly converted to type object or to any interface type implemented by value type. Boxing is a process in which object instances are created and copy values in to that instance. Unboxing is vice versa of boxing operation where the value is copied from the instance in to appropriate storage location. Below is sample code of boxing and unboxing where integer data type is converted in to object and then vice versa.
Dim x As Integer
Dim y As Object x = 10
' boxing process
y = x
' unboxing process
x = y

You can also find related Interview Question to What is concept of Boxing and Unboxing ?  below: 

What is concept of Boxing and Unboxing?

  
Boxing permits any value type to be implicitly converted to type object or to any interface type
implemented by value type. Boxing is a process in which object instances are created and copy
values in to that instance.

Unboxing is vice versa of boxing operation where the value is copied from the instance in to
appropriate storage location. (More...)

What is boxing and unboxing?

  
Converting a value type to reference type is called Boxing and Converting reference type of value type is Unboxing.

int i = 1;
object o = i; // boxing
int j = (int) o; // unboxing (More...)

What is boxing and unboxing explain with example?

  
The example

class Test
{
static void Main() {
int i = 1;
object o = i; // boxing
int j = (int) o; // unboxing
}
}

An int value can be converted to object and back again to int.
This example shows both boxing and unboxing. When a variable of a value type needs to be converted to a reference type, an object box is allocated to hold the value, and the value is copied into the box.

Unboxing is just the opposite. When an object box is cast back to its original value type, the value is copied out of the box and into the appropriate storage location. (More...)

What is boxing and unboxing?

  
Boxing is the process in which a object instances created and copying value type values to it. Unboxing is vice versa of boxing operation in which the value is copied from the instance into appropriate storage location. (More...)

What is Boxing and unboxing ?

  
Boxing:
The conversion of a value type instance to an object, which implies that the instance will carry full type information at run time and will be allocated in the heap. The Microsoft intermediate language (MSIL) instruction set's box instruction converts a value type to an object by making a copy of the value type and embedding it in a newly allocated object.

Un-Boxing:
The conversion of an object instance to a value type.
(More...)

What is boxing and unboxing?

  
==Boxing
Value type to object type. Allocates memory on Heap.

==UnBoxing
Object type to value type. Allocates memory on Stack.
(More...)

Difference between Boxing and unboxing?

  
Boxing: Convert value type to reference type.
UnBoxing:Convert Reference type to value Type.
(More...)

Difference between Boxing and unboxing?

  
Boxing: Convert value type to reference type.
UnBoxing:Convert Reference type to value Type. (More...)

What is boxing and unboxing ?

  

he operation of Converting a Value Type to a Reference Type is called Boxing
Boxing Example:

int Var = 1; //This is a value type

Object Obj = Var; //Boxing we assign a value type into a reference

An unboxing conversion permits an explicit conversion from type object to any value-type

int Var = 1;

Object Obj = Var; //Boxing

int i = (int)Obj; //Unboxing (More...)

Explain the concept of Reentrancy?

  
It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part, but has its own copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.

Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure. (More...)

What is Data Model concept?

  
Data Model is a collection of conceptual tools for describing data, data relationships data semantics and constraints. (More...)

What is "Locking" concept in DBMS?

  
Locking is the most common type of concurrency control mechanism. In this approach, any data is retrieved by an active user for updating, must be locked or denied to other users until updating is not complete. (More...)

How the concept of method overriding different from method overloading?

  
When overriding occurs on a method, you can change the behavior of the method for the class you have derived. Overloading a method involves in having another method with the same name within the class. (More...)

What is the concept of strong names ?

  
Strong name is similar to GUID(It is supposed to be unique in space and time) in COM
components.Strong Name is only needed when we need to deploy assembly in GAC. Strong
Names helps GAC to differentiate between two versions. Strong names use public key cryptography
(PKC) to ensure that no one can spoof it.PKC use public key and private key concept. (More...)

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