Public Sub RenameCtrl(ByVal Contenitore As Control) 'la prima volta che richiami la funzione gli passi la Form
        Dim zCtrl As Control
        For Each zCtrl In Contenitore.Controls
            Select Case zCtrl.GetType.ToString
          ....
   Case "System.Windows.Forms.GroupBox"
                    RenameCtrl(zCtrl)
Case "System.Windows.Forms.Label"
ctrl.text = "testo"
                   Case "System.Windows.Forms.Panel"
                    RenameCtrl(zCtrl)
               Case "System.Windows.Forms.TabControl"
                    RenameCtrl(zCtrl)
                Case "System.Windows.Forms.TabPage"
                    RenameCtrl(zCtrl)
               ...
            End Select
        Next zCtrl
    End Sub