'erstes Steuerelement ListBox(Dock: Fill, Name: lst)
'zweites Steuerelement TextBox(Name: txtEdit, BorderStyle = None)
Public Class MyListBox
    Private Sub lst_SelectedIndexChanged(ByVal sender As System.Object, ByVal e _
      As System.EventArgs) Handles lst.SelectedIndexChanged
        Try
            txtEdit.Text = lst.SelectedItem
            txtEdit.Visible = True
            txtEdit.Left = 0
            txtEdit.Top = lst.ItemHeight * lst.SelectedIndex
            txtEdit.Width = lst.Width
            txtEdit.Height = lst.Height
            txtEdit.Font = lst.Font
            txtEdit.Focus()
            txtEdit.SelectionStart = txtEdit.Text.Length
            txtEdit.SelectionLength = 0
        Catch ex As Exception
 
        End Try
    End Sub
    Sub Übernehmen()
        Try
            lst.Items.Item(lst.SelectedIndex) = txtEdit.Text
        Catch ex As Exception
 
        End Try
    End Sub
    Private Sub txtEdit_KeyDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles txtEdit.KeyDown
        If e.KeyCode = Keys.Enter Then
            Übernehmen()
            lst.Focus()
        End If
    End Sub
End Class