How to get parent custom fields?

[ArtJensenDK]

I'm trying to write a rule that rolls down some custom fields from parents to children.

I have used:
var parentWorkItem = self.Parent;
self["Custom.Customer"] = parentWorkItem**.Title**;

• But I can only figure out how to do that with a parent's standard fields like ".Title, .State, .Id, etc..".
• I am trying to get the custom field from a parent, but "parentWorkItem.Custom.Xxx" doesn't work.

Does anyone know how to get the parent's custom fields?