Generics in VB.NET

This article shows Generics in VB.NET.
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In this article we will learn how to use generics in VB.NET

Generics means you can use a generic type parameter P to write a class TheList<T> and that class can be used as TheList<int>, TheList<boolean> or even TheList<MyClass> and not have to worry about runtime conversion or illegal conversion/cast errors.

-    A system to define type of elements inside a class while creating object of the class.

-    All such collections are provided under System.Collections.Generic namespace.

          List<>


 

Example1:

 

Module Module1

    Class GenericTest

           Public Shared Sub Main()

            Dim ar As New List(Of Integer)()

            ar.Add(56)

            ar.Add(55)

            ar.Add(34)

            Dim sum As Integer = 0

            For i As Integer = 0 To ar.Count - 1

                sum += ar(i)

            Next

            Console.WriteLine(sum)

        End Sub

    End Class

 End Module

 

OUTPUT:

 

  generic.gif

 

Example 2: Generic string List

 

Imports System

Imports System.Collections

Imports System.Collections.Generic

 

Public Class generic

 

    Shared Sub Main(ByVal args As String())

        Dim places As New List(Of String)

        places.Add("A")

        places.Add("B")

        places.Add("C")

        places.Add("d")

    End Sub

  End Class


 

Advantages of Generics:
 

  1. Type Safety. Generic types enforce compile-time type checking. Types based on Objectaccept any data type, and you must write code to check whether an inputdata type is acceptable. With generic types, the compiler can catch type mismatches before run time.
  2. Performance. Generic types do not have to box and unbox data, because each one is specialized for one data type. Operations based on Object must box input data types to convert them to Object and unbox data destined for output. Boxing and unboxing reduce performance.

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