Action to perform when closing a window?

[ravan56]

I want to make sure an application closes the serial port it’s using when the window is closed using the red X in windows. Is there a way to perform some specific case or something similar when that button is hit before the window closes?

[GerdW]

copied from Reddit…

[crossrulz]

Event Structure. The event you want to use is the <This VI>->Panel Close event. This will be triggered when you try to close the window. What I usually do is use the Filter Event version (has the ? at the end of the name). I then discard the event (stopping the closing of the window), stop the loop, and then do whatever extra clean up is required after the loop. I can then use the Front Panel->Close method to close the window if so desired.