How can I get all selected collections in the Outliner?

Question

In 2022 there was an answer to a question over at devtalk.blender.org about selecting multiple collections.

The answer was this code segment:

import bpy

# Set the area to the outliner
area = bpy.context.area
old_type = area.type 
area.type = 'OUTLINER'

# some operations
ids = bpy.context.selected_ids
names = [o.name for o in ids]
print (names)

# Reset the area 
area.type = old_type  

As it seems, this has worked in the version what was current at that time but it doesn't work in 3.6 anymore. The list remains empty regardless of what is selected in the Outliner.

It was a very elegant solution to get more than one selected collection.

Can this be made working again in 3.6?

In the 3.6 documentation bpy.context.selected_ids is listed under View_3D context. Does this mean that it is now only available in the View_3D area and no longer in the Outliner?

Answer 1

You can use context override instead. The Outliner you temporarily opened with the statement area.type = 'OUTLINER', which is essentially another instance of that area, didn't retain the collections you had selected. Those selections were only applied to the Outliner area that is open by default when you open Blender, which is why the list turned up empty.

The following solution tackles the problem by pinpointing the specific Outliner area, of which there's typically just one, and then delving into its context to fetch the list of selected collections. If you don't have an Outliner open, this approach will naturally result in an error. And in cases where there are two (like in the Scripting tab) or more Outliners open, the method will focus on the first area instance that you get with next keyword.

import bpy

def print_selected_collections():
    ids = bpy.context.selected_ids
    names = [o.name for o in ids]
    print(names)

area  = next(area for area in bpy.context.window.screen.areas if area.type == 'OUTLINER')

with bpy.context.temp_override(
    window=bpy.context.window,
    area=area,
    region=next(region for region in area.regions if region.type == 'WINDOW'),
    screen=bpy.context.window.screen
):
    print_selected_collections()