Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Me.MachDingsda(Me)
    End Sub
 
    Private Sub MachDingsda(container As Control)
        For Each ctrl As Control In container.Controls
            If TypeOf ctrl Is TextBox Then Me.MachWasAnderes(ctrl)
            If ctrl.HasChildren Then Me.MachDingsda(ctrl)
        Next
    End Sub