how to work with generic classes in VB.NET

Whenever you need to work with a collection of objects you use generic collection. .NET framework providing some generic collection such as the ones define by the List(), SortedList(), Stack(), Queue() classes.

So many times you need to use generics to define your own generic collection to add some functionality which is not provided in .NET Framework generic collections. So, this article show you how to do that.
 
In this example first creates a CustomList() class that can store Product types, add four product object to the list, and display these objects in a dialog box.

EXAMPLE CODE
Imports System.Windows.Forms
Module Module1
    Public Class CustomList(Of T)
        Private List As New List(Of T)

        Public Sub Add(ByVal item As T)
            List.Add(item)
        End Sub

        Default Public Property Item(ByVal indax As Integer) As T
            Get
                Return List(indax)
            End Get
            Set(ByVal value As T)
                List(indax) = value
            End Set
        End Property

        Public ReadOnly Property Count() As Integer
            Get
                Return List.Count
            End Get
        End Property

        Public Overrides Function ToString() As String
            Dim listString As String = ""
            For i As Integer = 0 To List.Count - 1
                listString &= List(i).ToString & vbCrLf
            Next
            Return listString
        End Function
    End Class

    Sub Main()
        Dim list As New CustomList(Of Integer)
        Dim a1 As Integer = 23
        Dim a2 As Integer = 71
        Dim a3 As Integer = 10
        Dim a4 As Integer = 50
        list.Add(a1)
        list.Add(a2)
        list.Add(a3)
        list.Add(a4)
        MessageBox.Show(list.ToString, "List of Integers")
    End Sub
End Module

OUTPUT