If you want to allow the user to select more than 1 entry I would suggest using a list box control and changing the selection mode property rather than using a combo box because combo boxes should really only be used to select a single value.
You don't actually ask a question you've just stated that you need to update a table but I'm guessing you want to know how to update a table where the value of a record is the same as the name selected?
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 ...