ARTICLE

Boxing and Unboxing

Posted by Puran Mehra in Articles | Visual Basic 2010 on August 25, 2009

In this article I will explain you about Boxing and Unboxing in VB.NET.

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Reader Level: Beginner

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:

Conclusion:

Hope the article might have helped you in understanding Boxing and Unboxing.

Your feedback and constructive contributions are welcome. Please feel free to contact me for feedback or comments you may have about this article.