[RESOLVED] [2005] Generics (Of T)

Hello everyone. I'm struggling to get my head around generics, so I decided to make an example.

I added a new class and typed :

Code:

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Public Class MyGenericList(Of T)
    Implements ICollection
    Implements IEnumerable

    Public InnerList As ArrayList = New ArrayList()

    Public Sub Add(ByVal val As T)
        InnerList.Add(val)
    End Sub

    Default Public ReadOnly Property Item(ByVal index As Integer) As T
        Get
            Return CType(InnerList(index), T)
        End Get
    End Property
End Class

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As I understand, this will enable me to add Integers, Strings or whatever separately to this list, so this is what I did inside my Form

Code:

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Public Class Form1
    Private IntList As New MyGenericList(Of Integer)()
    Private StringList As New MyGenericList(Of String)()


    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        IntList.Add(0)
        IntList.Add(1)
        IntList.Add(2)
        IntList.Add(3)
        IntList.Add(4)

        StringList.Add("Zero")
        StringList.Add("One")
        StringList.Add("Two")
        StringList.Add("Three")
        StringList.Add("Four")
    End Sub

    Public Sub Display(Of T)(ByVal list As MyGenericList(Of T))
        For Each obj As T In New List(Of T)()
            Console.WriteLine(obj.ToString)
        Next
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim list As New MyGenericList(Of Integer)
        Display(Of Integer)(list)

    End Sub
End Class

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But nothing gets outputted to the Output window.

I'd just like to know how I can enumerate the items in my generic list. Can anyone help? :cry:

Don't worry, I fixed it myself. This is what I did:

Generic Class:

Code:

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Public Class MyGenericList(Of T)
    Inherits CollectionBase
    Implements ICollection

    Public Function Add(ByVal value As T) ' As T
        Return List.Add(value)
    End Function

    Public Sub Remove(ByVal value As T)
        List.Remove(value)
    End Sub

    Public ReadOnly Property Item(ByVal index As Integer) As T
        Get
            Return CType(List.Item(index), T)
        End Get
    End Property

End Class

---

Form:

Code:

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Public Class Form1
    Private IntList As New MyGenericList(Of Integer)()
    Private StringList As New MyGenericList(Of String)()
    Private ButClicked As Integer

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        IntList.Add(0)
        IntList.Add(1)
        IntList.Add(2)
        IntList.Add(3)
        IntList.Add(4)

        StringList.Add("Zero")
        StringList.Add("One")
        StringList.Add("Two")
        StringList.Add("Three")
        StringList.Add("Four")

    End Sub

    Public Sub Display(Of T)(ByVal list As MyGenericList(Of T))
        Select Case ButClicked
            Case 0
                For Each obj As T In IntList
                    Console.WriteLine(obj.ToString)
                Next
            Case 1
                For Each obj As T In StringList
                    Console.WriteLine(obj.ToString)
                Next
        End Select

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ButClicked = 0
        Dim list As MyGenericList(Of Integer)
        Display(Of Integer)(list)
    End Sub

    Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
        ButClicked = 1
        Dim list As MyGenericList(Of String)
        Display(Of String)(list)
    End Sub
End Class

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