Boxing And Unboxing

Overview

• Boxing is an implicit conversion of a value type to the object type.
  • Boxing a value type will copy the value to the heap, and place a reference to the boxed value on the stack.

Good practice

• Try to avoid boxing/unboxing when possible; use generics or multiple overloads instead.
  • Read Boxing/Unboxing In .NET for performance tests.

Examples

Boxing Operation

int i = 123;
object o = (object)i;

Unboxing Operation

object o = 123;
int i = (int)o;