Private Sub Form1_Closing(ByVal sender As Object, ByVal e As _
   System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        ' Ereignis der TextBox entfernen
        RemoveHandler TextBox1.TextChanged, AddressOf Me.TextBox1_TextChanged
        ' Obj aus dem Speicher entfernen
        Me.TextBox1.Dispose()
        Me.TextBox1 = Nothing
    End Sub