I'd recommend getting used to programming command line programs in Java before hopping into GUI's. I recommend this because a lot of the underlying functionality is key to writing a good program. If you start at GUI's, you tend to focus more on interface design and less on the program functionality.
If you choose to take this advice, have a look at the following:
Object Oriented Design
Java Collections (ArrayList, HashMap, HashSet, Array)
These will give you a good foundation to writing Java programs.
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 ...