Do something when an enumerator is changed

Question

When I choose an option for one of my enumators in my script, I can tell from the "info" space that there is a command:

bpy.context.scene.extra.[name of enumerator] = '[option]'

I want to have the script do something whenever this command happens, or just whenever the enumerator is changed in general, but I don't know how.

Answer 1

I figured out how to do it with a "Message Bus". I put the following script under def register()::

def register():
    owner = bpy.types.Scene.extra
    key = bpy.context.scene.path_resolve("extra.Enumerator_name", False)
    bpy.msgbus.subscribe_rna(key=key, owner=owner, args=(), notify=doSomething,)

What the code does is it effects doSomething whenever the enumerator is changed. To set up doSomething, you just do the following: type "def doSomething(*args):" somewhere in your script and then put whatever it is you want to happen after that. Here are the sources I used in case you want to check it out: https://docs.blender.org/api/current/bpy.msgbus.html and Using Message Bus to trigger events based on custom property changes

Answer 2

Why don't you use Update? It seems to be very easy:

import bpy

def update_func(self, context):
    print("Updated: ", self.testprop)

bpy.types.Scene.testprop = bpy.props.FloatProperty(update=update_func)

bpy.context.scene.testprop = 11.0