How to make a drop down menu defined in a different operator/class?

Question

I'm trying to create a drop-down menu in a custom panel in my add-on.

I created an operator housing just the enumerator:

class RENDER_PT_render_finish_mode(bpy.types.Operator):
    """Select a mode"""
    bl_label = "Render Finish Mode"
    bl_idname = "render.finish_mode"
    bl_options = {'REGISTER', 'UNDO'}
    
    rf_enum : bpy.props.EnumProperty(
        name= "Render Finish Mode:",
        description = "Choose what to do when render has finished.",
        items = [ 
            ('OP1', "Shutdown", "Shuts down when finished"),
            ('OP2', "Hibernate", "Hibernates when finished")            
        ]
    )

And later on, within my panel I did this:

[Panel intro, other items...]
    [draw code]

        row.scale_y = 1.0
        layout.prop(RENDER_PT_render_finish_mode, "rf_enum")

[rest of panel...]

What should this say instead of RENDER_PT_render_finish_mode?

That's presumably the bit that's incorrect, but how do I reference the operator class containing my enum?

I'd already tried having the enumerator done entirely in the panel class, but couldn't get that to work either. Maybe that would be the better way to do it if I knew how.

Answer 1

Just for the sake of completion (as late as it may be), I'm posting the resolution as an actual answer here for future reference. I'm largely parroting what was in the comments, but at least it's easier to find and read for whoever next stumbles into this.

As Gorgious said in the comments, you can't do it like this. The best way to do it is to have it all contained in one operator.

You have your enumerator, then you use the invoke method to call a small popup window which contains your menu.

Here's how I did it (using dummy code):

enum-ref : bpy.props.EnumProperty(
    name= "this name appears near your menu.",
    default= 0,
    description = "Tooltip here.",
    items = [ 
        ('OP1', "Name for setting 1", "Tooltip for setting 1"),
        ('OP2', "Name for setting 2", "Tooltip for setting 2")   
        #etc...       
    ]
)

def invoke(self, context, event):
    wm = context.window_manager
    return wm.invoke_props_dialog(self)

def draw(self, context):
    layout = self.layout
    layout.prop(self, 'enum-ref')
    
def execute(self, context):
    if self.rf_enum == 'OP1':
        #do stuff corresponding to setting 1
    if self.rf_enum == 'OP2':
        #do stuff corresponding to setting 2            
    #and so on...
    return {'FINISHED'}

Nothing spectacular here, again. I think this is fairly standard and widely known/done, but for the benefit of people who aren't as experienced in python/ bpy (like myself), this may still be useful to see written in black and white.

Bear in mind that the execute method is called when a person clicks to confirm their setting after choosing it, which also makes the popup window disappear.