Private Sub Form1_Load(ByVal sender As System.Object, ByVal e _
     As System.EventArgs) Handles MyBase.Load
   'Controls in der Form
  For Each ctrl As Control In Me.Controls
     'RadioButtons auf Formularebenen
    If TypeOf ctrl Is RadioButton Then
      Dim rb As RadioButton = DirectCast(ctrl, RadioButton)
      AddHandler rb.CheckedChanged, AddressOf _
         RadioButton_CheckedChanged
    End If
     'Controls in GroupBoxen
    If TypeOf ctrl Is GroupBox Then
       'RadioButtons in GroupBoxen
      For Each ctrl2 As Control In ctrl.Controls
        Dim rb As RadioButton = DirectCast(ctrl2, RadioButton)
        AddHandler rb.CheckedChanged, AddressOf _
           RadioButton_CheckedChanged
      Next
    End If
  Next
End Sub

Private Sub RadioButton_CheckedChanged(ByVal sender As _
    System.Object, ByVal e As System.EventArgs)
  Label1.Text = DirectCast(sender, Control).Name
End Sub