box and unbox in C#

Question

describe box and unbox with example how it is stored in heap and stack.

Prabhu Raja · Answer

For your Reference http://iamprabhuraja.wordpress.com/?s=boxing+and+unbox

Jignesh Trivedi · Answer

Hi Boxing is the process of converting a value type to the type object or to any interface type implemented by this value type. Boxing is used to store value types in the garbage-collected heap. Boxing is an implicit conversion of a value type to the type object or to any interface type implemented by this value type. Unboxing is an explicit conversion from the type object to a value type or from an interface type to a value type that implements the interface. int temp1 = 999; // a value type object tempObj = i; // boxing int temp2 = (int)tempObj; // unboxing please refer http://www.codeproject.com/Articles/2225/Boxing-and-unboxing-in-C http://www.csharphelp.com/2006/02/boxing-and-unboxing-c/ hope this will help you.

Vulpes · Answer

When you assign a value type to an object or interface variable then it first needs to be converted to a reference type so that it can be stored on the heap using a process known as 'boxing'. A reference to the 'box' is then assigned to the object or interface variable. When the value type needs to be retrieved it needs to be 'unboxed' using a cast and then copied back to a variable of the value type. This variable will be stored on the stack (if it's a local variable or value parameter) or the heap otherwise (field array element etc). For example: int i = 3; object o = i; // 3 is boxed on heap int j = (int)o; // 3 is unboxed and copied to the variable j o = null; The last line means that there are no longer any references to the box and so it can be garbage collected in due course.