boxing is conversion from value type to object(reference) 
type.Actually the copy of value type copied from stack to 
heap memory.
unboxing is reverse of it.from heap memory back to stack 
memory.

Boxing and Un-boxing

Boxing allows value types to be implicitly treated like 
objects.

Dim i As Integer = 5
i.ToString()   ' i --> object --->object.tostring

OR

Dim i As Integer = 5
Dim obj As Object = i  ' implicit boxing 
obj.ToString()

OR you can do it explicitly
Dim obj As Object = CType(i, Object) ' un-necessary 
explicit boxing

On the other hand, un-boxing is an explicit conversion from 
object type to value type.

Dim i As Integer = 5
Dim obj As Object = i   ' implicit boxing 
Dim j As Integer = CType(obj, Integer)  ' explicit un-boxing



?	Boxing and Un-boxing is the transformation between 
value type and object type while casting just transforms 
the apparent (reference) type of objects. 
?	Value types are stored at the stack and objects are 
stored at the heap. 
Boxing takes a copy of value types from the stack to the 
heap while un-boxing takes value types back to the stack. 
On the other hand, casting does not physically move or 
operate on an object. Casting merely changes the way 
objects are treated in a program by altering their 
reference type.

BOXING
?	Boxing is an implicit conversion of a value type to 
the type object

UNBOXING
?	Unboxing is an explicit conversion from the type 
object to a value type

There is two type datatype available Value and reference 
type . value are stored in stack and reference type used 
in  heap . when we copy data from stack memmory to heap it 
call Boxing . 


Int32 x = 10;         object o = x ;  // Implicit 
boxing               
 Int32 y = 10;

unboxing : copy data from heap memory to stack called 
unboxing      
   object obj = (object) y; // Explicit Boxing


Rahul Tripathi 
raultripathi@myway.com

Boxing;
Encapsulating a copy of value in an object.
UnBoxing:
Vice-versa

boxing is used to convert value type to reference type.
unboxing is used to convet reference type to value type.