TIP : using onDataChange on unstored calculation

Classic Servoy
1

Hi,

if often have two columns in a listview which depend on each other.

For instance discount = ((gross_price - net_price)/gross_price)*100.0

and net_price = ((100.0-discount)/100.0) * gross_price

I want the user to be able to type a discount, but also to type a net_price and in both cases the other value must be calculated.
And i do not want to store both values in the database.

What i tested now is :

  • create database fields net_price and gross_price

  • create an unstored calculation discount with the formula :

return ((gross_price - net_price)/gross_price)*100.0;
  • set the unstored calculation editable
  • create an onDataChange method on the unstored calculation field :
var _discount = arguments[1]
net_price= ((100 - _discount) / 100) * gross_price

Works excellent !!!

Regards,

Hans

In the previous 4Gl I used

2

great tip!

thanks for sharing.