In fact most real projects DO code a lot of Swing code by hand, simply because most GUI builders produce such terrible results or results that aren't portable between environments (they put in their own classes which people on the team using other tools won't have, and sometimes are stupidly disallowed from distribution with the application).
And of course, if you don't learn how to do things, you never learn.
OP wants to learn how to write Swing code, but all you tell him is not to bother and use a graphical tool to plug things together.
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 ...