I have a dataobject in which I need relation data for a function on the first onBeforeWrite. The relation is set with DropdownField populated with a toDropdownMap in the CMS. In theory I should be able pull the ID from that form element but I'm not sure how its passed to the onBeforeWrite function. Calling $this->RelatedDataObejct doesn't work because that relation isn't set yet. And I can't get the form Value with $this->getField();

I could call the function I need in onAfterWrite and only fire it if the value I'm creating is null and putting another write function in it but that just seems like a recipe for disaster with potential write loops

Any ideas?

The relation is still null at onBeforeWrite the first time. It doesn't get created until the actual write. I'm talking about the initial creation of the record

I got fixed, the DataObject in question was an extension of DataObjectAsPage so I wrapped the functions in my onBeforeWrite in a if($this->ID !=0). I'll post that it needs to be documented