Option Strict On : Option Explicit On : Option Infer Off
 
Public Class cListbox(Of T)
    Inherits System.Windows.Forms.ListBox
    ''' <summary>Alle Items löschen</summary>
    Public Sub Clear()
        MyBase.Items.Clear()
    End Sub
 
    ''' <summary>Anzahl der Items (schreibgeschützt)</summary>
    Public ReadOnly Property Count() As Integer
        Get
            Return MyBase.Items.Count
        End Get
    End Property
 
    ''' <summary>Enthält die Listbox ein bestimmtes Item?</summary>
    ''' <param name="value">zu suchendes Item</param>
    ''' <returns>true: Item ist vorhanden</returns>
    Public Overloads Function Contains(ByVal value As T) As Boolean
        Return MyBase.Items.Contains(value)
    End Function
 
    ''' <summary>Gibt den kleinsten Index des Items in der Listbox zurück</summary>
    ''' <param name="value">zu suchendes Item</param>
    ''' <returns>Kleinster Index des Items</returns>
    Public Function IndexOf(ByVal value As T) As Integer
        Return MyBase.Items.IndexOf(value)
    End Function
 
    ''' <summary>Item an die Listbox anhängen</summary>
    ''' <param name="item">anzuhängendes Item</param>
    ''' <returns>Listbox-Index des Items</returns>
    Public Function Add(ByVal item As T) As Integer
        Return MyBase.Items.Add(item)
    End Function
 
    ''' <summary>Anzuhängende Items</summary>
    Public Overloads Sub AddRange(ByVal items() As T)
        For i As Integer = 0 To items.Length - 1
            Me.Add(items(i))
        Next i
    End Sub