You can't, that's a TV myth. Zooming in on a black pixel just makes a larger black pixel. There are no super algorithms that will make the zoom image show you more detail, as there is no more detail to show.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...