Control to save or undo without save

[Barcode]

Hello
When I make a new post and fill one of the fields,
I have a probem,it comes a message which tell us the primary
key can not be null,
I want to undo the post, otherwise I must close the program
and restart it again or continue doing the post, so what do
you recommend about this problem?

Thanks

 

[Evi]

Press Escape twice on your keyboard
Evi