Extra services

So if I understand the requirement correctly, you want that when checkbox is checked, the value of that custom field will be added to total registration fee?

If so, I think the code be added below this line in calculateIndividualRegistrationFee

You can add the below code:

if (isset($data))
{
$totalAmount += $feeCalculationTags;
}

The array $feeCalculationTags contains value of the event custom fields already. So the code above can be read at:

If the checkbox is checked, total registration fee will be added with the value of the custom field setup in the event

Not sure if it is clear (and I understand your need correctly)

BTW, for please submit a support ticket sending us PayPal Transaction ID of your Events Booking (or the email you used to purchase the product so that we can verify your order). At the moment, I could not find any order from your account or from your company domain

Regards,

Tuan

This is our second account. Our main account is Leszek Skurski. You allready helped us in the past. I'm talking about the Checkbox "Individuelle Begleitung kostenpflichtig buchen für 1 Teilnehmer / 90 Minuten (+100€ zzgl. MwSt.)". "(+100€ zzgl. MwSt.)" is generated from the custom field in the picture. This works fine. But currently the value that is added to the total amount comes from the custom field of the registration form not from the custom field of the event (in the picture).
Your code causes an "Unsupported operand types" error. Do you know what I'm trying to archive? Thank you for your support so far.

Best regards
Sebastian

I guess I understand your need now. I didn't notice that my some part of my code was stripped. To help me understand it easier, I think you can submit a support ticket sending me super admin account of your site

If I understand your need correctly, I can help with this modification

Tuan