Extends CollectionBase to create custom Collection : CollectionBase « Collections « VB.Net Tutorial

1. VB.Net Tutorial
2. Collections
3. CollectionBase

Imports System.Collections
Imports System.Collections.Generic
Imports System.Collections.Specialized

public class Test
  
   public Shared Sub Main
        Dim emp_list As New EmployeeCollection
        emp_list.Add(New Employee("A", "A"))
        emp_list.Add(New Employee("B", "B"))
        emp_list.Add(New Employee("C", "C"))
        emp_list.Add(New Employee("D", "D"))
        emp_list.Add(New Employee("E", "E"))

        For Each emp As Employee In emp_list
            Console.WriteLine(emp.ToString)
        Next emp
   End Sub
   
End class
Public Class Employee
    Private m_FirstName As String
    Private m_LastName As String
    Public Sub New(ByVal first_name As String, ByVal last_name As String)
        m_FirstName = first_name
        m_LastName = last_name
    End Sub
    Public Overrides Function ToString() As String
        Return m_FirstName & " " & m_LastName
    End Function
End Class

Public Class EmployeeCollection
    Inherits CollectionBase

    Public Sub Add(ByVal value As Employee)
        List.Add(value)
    End Sub

    Public Function Contains(ByVal value As Employee) As Boolean
        Return List.Contains(value)
    End Function

    Public Function IndexOf(ByVal value As Employee) As Integer
        Return List.IndexOf(value)
    End Function

    Public Sub Insert(ByVal index As Integer, ByVal value As Employee)
        List.Insert(index, value)
    End Sub

    Default Public ReadOnly Property Item(ByVal index As Integer) As Employee
        Get
            Return DirectCast(List.Item(index), Employee)
        End Get
    End Property

    Public Sub Remove(ByVal value As Employee)
        List.Remove(value)
    End Sub
End Class

A A
B B
C C
D D
E E