CiviCRM Community Forums (archive)

I need to
- have the user be able to select the membership type (each has a different associated fee)
- donate an amount if he wants to
- (here's the kicker) automatically calculate another fee based on the number of apartment units he manages and store that as a separate field, if more than 100 units, they are charged for #units * $0.20
- be able to total them all at check out

And, this apt management fee is only applied to certain membership types, not all.

I am delving into CiviCRM/CRM/Contribute/Form/Contribution/Main.php, specifically the "public function computeAmount".

So far, I only have:
if ( $params['custom_6'] > 100 ) {
   $amount = $amount + ((((int)$params['custom_6']) - 100) * .20);
}

- How do determine the membership types?

- How do I save the apartment fee separately?

Many thanks for any help!

thanks.