I have this program in which I need to calculate a price of something. This is easily done, however I don't want to calculate the price in the GUI, coz that would be a huge waste of CPU to calculate it 1000 times each second.
Is there some kind of method to know and react to change in dropdown menues?
User changes value of dropdown / writes own value in an input field. Then, and only then, will the function be called that does the calculating.