I want to create an event receiver that I'll attach it to content types across 4 site collections. The content type is being made programmatically, so no XML definition.
Also, I want to create an event receiver that I'll attach it to multiple lists across 4 site collections.
Are these possible?The problem I ran is that I need to "hook" it to a list, so which list?
You can create your content type, attach an event receiver to it, you don't need to create the event receiver by adding a new item in Visual Studio. Instead you add a class file write your event receiver from scratch inherting from SPItemEventReceiver, then add your content type to your lists. That way, the content type (with the event receiver) will be reusable on all lists it's added to.
Refer to this article for more info:
http://sharepoint-magic.blogspot.com/2013/06/content-type-event-receiver.html
And this one:
https://karinebosch.wordpress.com/walkthroughs/event-receivers-walkthrough3/
