Boxing And Unboxing In VB.NET

Boxing is simply the process of converting a value type to any interface type implemented by the current value type; the most common being the Value object. Boxing is used to store value types in the garbage-collected heap.

This means that, once a variable is boxed, it can hold a separate value in a separate memory location. When a value type is boxed, a new object must be allocated and constructed.

Boxing and unboxing is an important concept in VB.NET's type system. With Boxing and Unboxing one can link between value-types and reference-types by allowing any value of a value-type to be converted to and from type object.

Boxing

• Boxing is a mechanism in which value type is converted into reference type.
• It is implicit conversion process in which object type (super type) is used.
• In this process type and value both are stored in object type

Unboxing

• Unboxing is a mechanism in which reference type is converted into value.
• It is explicit conversion process.

Program to show Boxing and Unboxing:

Module Module1
    Sub Main()
        Dim i As Integer = 10
        Dim j As Integer        ' boxing        Dim o As Object        o = i
        'unboxing        j = CInt(o)
        Console.WriteLine("value of o object : " & o)
        Console.WriteLine("Value of j : " & j)
        Console.ReadLine()
    End Sub
End Module

Output of above program: