VB.Net/Generics/Generic Class

Declare a generic type

  
Public Class Car
End Class
Module Program
  Sub Main()
    Dim myCars As New List(Of Car)
    myCars.Add(New Car())
    Console.WriteLine(myCars.Count)
    Dim MyInts As New List(Of Integer)
    MyInts.Add(50)
    Dim val As Integer = MyInts.Count
    Console.WriteLine(MyInts.Count)
  End Sub
End Module

Generic Class Demo

 
Public Class MainClass
   Public Shared Sub Main()
        Dim talker1 As New GenericTalker(Of Dog)()
        talker1.Talker = New Dog()
        talker1.sayHello()
        Dim talker2 As New GenericTalker(Of Cat)()
        talker2.Talker = New Cat()
        talker2.sayHello()
   End Sub

End Class
Public Class GenericTalker(Of T)
    Public Talker As T
    Public Sub SayHello()
        Dim helloWorld As String
        helloWorld = Talker.ToString()
        Console.WriteLine(helloWorld)
    End Sub
End Class
Public Class Dog
    Public Overrides Function ToString() As String
        Return "Dog!"
    End Function
End Class
Public Class Cat
    Public Overrides Function ToString() As String
        Return "Cat"
    End Function
End Class
Public Class Mouse
    Public Overrides Function ToString() As String
        Return "Mouse"
    End Function
End Class
Public Class Person
    Public Overrides Function ToString() As String
        Return "Person"
    End Function
End Class

Generic List stores Generic Class

 
Imports System.Collections
Imports System.Collections.Generic
Public Class MainClass
   Public Shared Sub Main()
        Dim custColl As New List(Of Customer)()
        Dim cust As New Customer("1", "Name")
        cust.AddItem(New Order(DateTime.Parse("10/01/2004"), "1", "N"))
        cust.AddItem(New Order(DateTime.Parse("10/03/2004"), "2", "X"))
        cust.AddItem(New Order(DateTime.Parse("10/07/2004"), "3", "P"))
        custColl.Add(cust)
        cust = New Customer("2", "name 1")
        cust.AddItem(New Order(DateTime.Parse("11/04/2004"), "6", "P"))
        cust.AddItem(New Order(DateTime.Parse("11/07/2004"), "8", "Y"))
        cust.AddItem(New Order(DateTime.Parse("12/12/2004"), "9", "K"))
        custColl.Add(cust)
        cust = New Customer("3", "Name 3")
        cust.AddItem(New Order(DateTime.Parse("10/01/2004"), "4", "W"))
        custColl.Add(cust)

        For custIdx As Int32 = 0 To (custColl.Count - 1)
            cust = custColl(custIdx)
            Console.Out.WriteLine("Customer-) ID: {0}, Name: {1}", cust.Id, cust.Name)
            Dim orders() As Order = cust.Items
            For orderIdx As Int32 = 0 To (orders.Length - 1)
                Dim ord As Order = orders(orderIdx)
                Console.Out.WriteLine("    Order-> Date: {0}, Item: {1}, Desc: {2}", ord.OrderDate, ord.ItemId, ord.Description)
            Next
        Next

        Dim empColl As New List(Of Employee)()
        Dim emp As New Employee("1", "R")
        empColl.Add(emp)
        emp = New Employee("2", "M")
        empColl.Add(emp)
        emp = New Employee("3", "B")
        emp.AddItem(New Employee("6", "S"))
        emp.AddItem(New Employee("7", "B"))
        emp.AddItem(New Employee("8", "T"))
        empColl.Add(emp)
        For mgrIdx As Int32 = 0 To (empColl.Count - 1)
            Dim manager As Employee = empColl(mgrIdx)
            Console.Out.WriteLine("Manager-) ID: {0}, Name: {1}", manager.Id, manager.Name)
            For idx As Int32 = 0 To (manager.Items.Length - 1)
                emp = manager.Items(idx)
                Console.Out.WriteLine("    Employee-) Id: {0}, Name: {1}", emp.Id, emp.Name)
            Next
        Next
   End Sub
End Class
Public Class Customer
    Inherits Person(Of Order)
    Public Sub New(ByVal Id As String, ByVal Name As String)
        MyBase.New(Id, Name)
    End Sub
End Class

Public Class Employee
    Inherits Person(Of Employee)
    Public Sub New(ByVal Id As String, ByVal Name As String)
        MyBase.New(Id, Name)
    End Sub
End Class

Public Class Order
    Public OrderDate As DateTime
    Public ItemId As String
    Public Description As String
    Public Sub New(ByVal OrderDate As DateTime, ByVal ItemId As String, ByVal Description As String)
        Me.OrderDate = OrderDate
        Me.ItemId = ItemId
        Me.Description = Description
    End Sub
End Class

Public Class Person(Of T)
    Public Name As String
    Public Id As String
    Private _items As List(Of T)
    Public Sub New(ByVal Id As String, ByVal Name As String)
        Me.Id = Id
        Me.Name = Name
        Me._items = New List(Of T)
    End Sub
    Public ReadOnly Property Items() As T()
        Get
            Return Me._items.ToArray()
        End Get
    End Property
    Public Sub AddItem(ByVal newItem As T)
        Me._items.Add(newItem)
    End Sub
End Class

Generic Point Structure

  

Option Explicit On
Option Strict On
Module Program
  Sub Main()
    Dim intPt As New Point(Of Integer)(100, 100)
    Console.WriteLine(intPt.ToString())
    Dim dblPt As New Point(Of Double)(5.6, 3.23)
    Console.WriteLine(dblPt.ToString())
    Dim p1 As New Point(Of Integer)(10, 43)
    Dim p2 As New Point(Of Integer)(6, 987)
    Console.WriteLine(p1)
    Console.WriteLine(p2)
    Swap(Of Point(Of Integer))(p1, p2)
    Swap(p1, p2)
    Console.WriteLine(p1)
    Console.WriteLine(p2)
  End Sub
  Public Function Swap(Of T)(ByRef a As T, ByRef b As T) As T
    Console.WriteLine("T is a {0}.", GetType(T))
    Dim temp As T
    temp = a
    a = b
    b = temp
  End Function
End Module
Public Structure Point(Of T)
  Private xPos, yPos As T
  Public Sub New(ByVal x As T, ByVal y As T)
    xPos = x : yPos = y
  End Sub
  Public Property X() As T
    Get
      Return xPos
    End Get
    Set(ByVal value As T)
      xPos = value
    End Set
  End Property
  Public Property Y() As T
    Get
      Return xPos
    End Get
    Set(ByVal value As T)
      yPos = value
    End Set
  End Property
  Public Overrides Function ToString() As String
    Return String.Format("({0}, {1})", xPos, yPos)
  End Function
End Structure