Boxing & UnBoxing In C#

C# is a strongly-typed language. Every variable and constant has a type, as does every expression that evaluates to a value. In this article I will share about understanding Boxing and UnBoxing in C#.

C# Type System contains three Types , they are Value Types , Reference Types and Pointer Types. C# allows us to convert a Value Type to a Reference Type, and back again to Value Types . The operation of Converting a Value Type to a Reference Type is called Boxing and the reverse operation
is called Unboxing.

Boxing:

Example

1: int akm = 1;
2: Object Obj = akm; //Boxing

The first line we created a Value Type akm and assigned a value to akm. The second line , we created an instance of Object Obj and assign the value of akm to Obj. From the above operation (Object Obj = i ) we saw converting a value of a Value Type into a value of a corresponding Reference Type . These types of operation is called Boxing.

UnBoxing

Example
1:Int akm=1;
2:Object Obj=akm; //Boxing
3:Int i=(int)Obj; //Unboxing
The first two line shows how to Box a Value Type . The next line (int i = (int) Obj) shows extracts the Value Type from the Object . That is converting a value of a Reference Type into a value of a Value Type. This operation is called UnBoxing.

Difference Between Boxing & UnBoxing

	Boxing	Unboxing
Definition:	Boxing is the process of converting a value type to the reference type.	Unboxing is the process of converting a reference type to value type .
Type of Conversion:	Implicit Conversion	Explicit Conversion
Example:	int akm = 221; object obj = akm; //boxing	object obj = 213; akm = (int)obj ; // unboxing