ArrayList Supports Notifications When Items Added or Removed

Public Class ArrayListChangedEventArgs     Inherits EventArgs     Public Sub New(list As CairoArrayList, action As ChangeAction)         Me.List = list         Me.Action = action     End Sub     Public Property List As CairoArrayList     Public Property Action As ChangeAction End Class ' ArrayListChangedEventArgs

Public Enum ChangeAction     Add     Remoce End Enum

Public Class CairoArrayList     Private _list As ArrayList     Public Sub New()         Me._list = New ArrayList     End Sub     Public ReadOnly Property Items As ArrayList         Get             Return Me._list         End Get     End Property     Public Sub Add(value As Object)         If Me._list IsNot Nothing AndAlso (Not Me._list.Contains(value)) Then             Me._list.Add(value)             Me.OnChanged(Me, New ArrayListChangedEventArgs(Me, ChangeAction.Add))         End If     End Sub     Public Sub Remove(value As Object)         If Me._list IsNot Nothing AndAlso (Me._list.Contains(value)) Then             Me._list.Remove(value)             Me.OnChanged(Me, New ArrayListChangedEventArgs(Me, ChangeAction.Remoce))         End If     End Sub     Public Function Contains(key As Object) As Boolean         Return Me._list IsNot Nothing AndAlso Me._list.Contains(key)     End Function     Protected Sub OnChanged(sender As Object, e As ArrayListChangedEventArgs)         RaiseEvent Changed(Me, e)     End Sub     Public Event Changed As EventHandler(Of ArrayListChangedEventArgs) End Class ' CairoArrayList

Usage:


Define CairoArrayList

Dim list As CairoArrayList = New CairoArrayList

Fill the list with data

list.Add("Cairo") list.Add("Alex") list.Add("Aswan")

Add Handler

AddHandler list.Changed, AddressOf OnListChanged

Do something when list changed

Private Sub Onlistchanged(sender As Object, e As EventArgs)         ' Do something when items dynamically removed or added to the list     End Sub