I have two forms, form 1 shows master and detail records, from 2 I use to add detail records, information is saved on database, before close Form 2, I refetch entity, but Form 1 does not show the record that was just added.

To see records I have to close Form 1 and open again

Please could you help me version 2.0 and C#

A simple way to manage this would be to open Form2 as a dialog. When it is closed refetch your records in Form1. This may be very similar to what you are doing it sounds like, so it may help to post an example of your scenario to see if we can provide a better answer.