How to implement Windows 10 IVirtualDesktopManager interface in Python?

Question

I'm trying to implement IVirtualDesktopManager interface (and hopefully IVirtualDesktopManagerInternal afterward) in Python based on this SO answer, but I'm stuck.

Edit: I want a working example in Python that will at least lead me to the implementation of IsWindowOnCurrentVirtualDesktop method - it should return a Boolean when a hwnd is passed to it.

Using pywin32 I'm able to get to some point in the process, but I'm not sure neither if I even can do that in pure Python nor how to continue:

# bypythoncom.py
import pythoncom
import pywintypes

"""IServiceProvider* pServiceProvider = NULL;
HRESULT hr = ::CoCreateInstance(
    CLSID_ImmersiveShell, NULL, CLSCTX_LOCAL_SERVER,
    __uuidof(IServiceProvider), (PVOID*)&pServiceProvider);"""

CLSID_ImmersiveShell = pywintypes.IID("{C2F03A33-21F5-47FA-B4BB-156362A2F239}")

provider = pythoncom.CoCreateInstance(
    CLSID_ImmersiveShell,
    None,
    pythoncom.CLSCTX_LOCAL_SERVER,
    pythoncom.IID_IServiceProvider,
)
print(provider)

"""if (SUCCEEDED(hr))
{
    IVirtualDesktopManager *pDesktopManager = NULL;
    hr = pServiceProvider->QueryService(__uuidof(IVirtualDesktopManager), &pDesktopManager);

    if (SUCCEEDED(hr))
    {
        BOOL bIsOnCurrentDesktop = FALSE;
        hr = pDesktopManager->IsWindowOnCurrentVirtualDesktop(hWnd, &bIsOnCurrentDesktop);

        if (SUCCEEDED(hr))
        {
            // use bIsOnCurrentDesktop as needed...
        }

        pDesktopManager->Release();
    }

    pServiceProvider->Release();
}
"""

manager = provider.QueryService(
    pywintypes.IID("{a5cd92ff-29be-454c-8d04-d82879fb3f1b}"),
    pythoncom.IID_IUnknown,
)
print(manager)

# C:\dev\examples\desktops>python bypythoncom.py
# <PyIServiceProvider at 0x002A7170 with obj at 0x001C256C>
# <PyIUnknown at 0x002A7188 with obj at 0x002AB2F4>

Using comtypes I don't know what to use as interface argument to QueryService:

# bycomtypes.py
import comtypes
import comtypes.client
from comtypes.GUID import GUID

clsid = GUID("{C2F03A33-21F5-47FA-B4BB-156362A2F239}")  # CLSID_ImmersiveShell

service_provider = comtypes.client.CreateObject(clsid, interface=comtypes.IServiceProvider)
print(service_provider)

iid = GUID("{A5CD92FF-29BE-454C-8D04-D82879FB3F1B}") # IID_IVirtualDesktopManager

manager = service_provider.QueryService(
    iid, interface
)

# C:\dev\examples\desktops>python bycomtypes.py
# <POINTER(IServiceProvider) ptr=0xbd8d04 at 30c8e90>

I'm not really sure what I should do after getting provider, IUnknown has only QueryInterface method exposed, here's another ctypes and comtypes try:

import ctypes
from comtypes import IUnknown, CLSCTX_LOCAL_SERVER
from comtypes.GUID import GUID

ole32 = ctypes.windll.ole32
# ole32.CoInitialize(None)

CLSID_ImmersiveShell = GUID("{C2F03A33-21F5-47FA-B4BB-156362A2F239}")
IID_IServiceProvider = GUID("{6D5140C1-7436-11CE-8034-00AA006009FA}")

provider = ctypes.POINTER(IUnknown)()
ole32.CoCreateInstance(
    ctypes.byref(CLSID_ImmersiveShell),
    None,
    CLSCTX_LOCAL_SERVER,
    ctypes.byref(IID_IServiceProvider),
    ctypes.byref(provider),
)
print(provider)

IID_IVirtualDesktopManager = GUID("{A5CD92FF-29BE-454C-8D04-D82879FB3F1B}")
instance = provider.QueryInterface(IUnknown, IID_IVirtualDesktopManager)

# C:\dev\examples\desktops>python byctypes.py
# <POINTER(IUnknown) ptr=0x8b294 at 8a26c0>
# Traceback (most recent call last):
#   File "another.py", line 22, in <module>
#     instance = provider.QueryInterface(IUnknown, IID_IVirtualDesktopManager)
#   File "C:\dev\venvs\project\lib\site-packages\comtypes\__init__.py", line 1158, in QueryInterface
#     self.__com_QueryInterface(byref(iid), byref(p))
# _ctypes.COMError: (-2147467262, 'No such interface supported', (None, None, None, 0, None))

Edit2: I changed the last example so it reveals what @Baget points at. An excerpt from the actual implementation in Python of comtypes.IUnknown's QueryInterface is:

def QueryInterface(self, interface, iid=None):
    "QueryInterface(interface) -> instance"
    p = POINTER(interface)()
    if iid is None:
        iid = interface._iid_

I would be grateful if someone gives a hint on how to do this or links some implementation I may follow to do the job.

You should also add to your question, what you are trying to achieve as a end goal — Tarun Lalwani, Jul 25 '19 at 07:32
The first sentence explains, I want to be able to run those three method from the interface in Python, linked SO answer in C++ deals with one of those methods and that's totally fine, the other two (and Internals interface probably) should be easy toimplement. — ipaleka, Jul 25 '19 at 10:27
See if this helps? https://github.com/DanEdens/Virtual_Desktops_Plugin/ — Tarun Lalwani, Jul 25 '19 at 14:41
Wow, that's it! :) **Please make an answer** from this comment, so I may accept it. There are some issues I've got (`pDesktopManagerInternal.GetDesktops(ctypes.byref(pObjectArray)) TypeError: call takes exactly 1 arguments (2 given)`, but that "problem" is what we call in Croatia "a p**sy smoke", kind of meaning "piece of cake to solve". :) — ipaleka, Jul 25 '19 at 16:14

score 4 · Accepted Answer · answered Jul 25 '19 at 17:17

You can take inspiration from below code to write your own

All credits to the original author on https://github.com/DanEdens/Virtual_Desktops_Plugin/

# -*- coding: utf-8 -*-
#
# This file is a plugin for EventGhost.
# Copyright © 2005-2019 EventGhost Project <http://www.eventghost.net/>
#
# EventGhost is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 2 of the License, or (at your option)
# any later version.
#
# EventGhost is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along
# with EventGhost. If not, see <http://www.gnu.org/licenses/>.

u"""
    Name: VirtualDesktops
    Author: Kgschlosser
    Version: 0.1
    Description: Creates events based on Virtual desktop interactions.
    GUID: {5DFFBD61-7582-4D6F-8EA9-9CB36284C9CF}
    URL: http://eventghost.net/forum/viewtopic.php?f=10&p=53389#p53389
"""
import eg

eg.RegisterPlugin(
    name = "Virtual Desktops",
    author = "Kgschlosser",
    version = "0.0.004",
    guid = "{C2F03A33-21F5-47FA-B4BB-156362A2F239}",
    canMultiLoad = False,
    url = "http://eventghost.net/forum/viewtopic.php?f=10&p=53389#p53389",
    description = "Creates events based on Virtual desktop interactions.",

)


from ctypes.wintypes import HRESULT, HWND, BOOL, POINTER, DWORD, INT, UINT, LPVOID, ULONG

import comtypes
import ctypes
from comtypes import helpstring, COMMETHOD
from comtypes.GUID import GUID

REFGUID = POINTER(GUID)
REFIID = REFGUID
ENUM = INT
IID = GUID
INT32 = ctypes.c_int32
INT64 = ctypes.c_int64

CLSID_ImmersiveShell = GUID(
    '{C2F03A33-21F5-47FA-B4BB-156362A2F239}'
)

CLSID_IVirtualNotificationService = GUID(
    '{A501FDEC-4A09-464C-AE4E-1B9C21B84918}'
)


class HSTRING__(ctypes.Structure):
    _fields_ = [
        ('unused', INT),
    ]


HSTRING = POINTER(HSTRING__)


class EventRegistrationToken(ctypes.Structure):
    _fields_ = [
        ('value', INT64)
    ]


class AdjacentDesktop(ENUM):
    LeftDirection = 3
    RightDirection = 4


class ApplicationViewOrientation(ENUM):
    ApplicationViewOrientation_Landscape = 0
    ApplicationViewOrientation_Portrait = 1


class TrustLevel(ENUM):
    BaseTrust = 0
    PartialTrust = BaseTrust + 1
    FullTrust = PartialTrust + 1


IID_IInspectable = GUID(
    '{AF86E2E0-B12D-4C6A-9C5A-D7AA65101E90}'
)


class IInspectable(comtypes.IUnknown):
    _case_insensitive_ = True
    _idlflags_ = []
    _iid_ = IID_IInspectable
    _methods_ = [
        COMMETHOD(
            [helpstring('Method GetIids')],
            HRESULT,
            'GetIids',
            (['out'], POINTER(ULONG), 'iidCount'),
            (['out'], POINTER(POINTER(IID)), 'iids'),
        ),
        COMMETHOD(
            [helpstring('Method GetRuntimeClassName')],
            HRESULT,
            'GetRuntimeClassName',
            (['out'], POINTER(HSTRING), 'className'),
        ),
        COMMETHOD(
            [helpstring('Method GetTrustLevel')],
            HRESULT,
            'GetTrustLevel',
            (['out'], POINTER(TrustLevel), 'trustLevel'),
        ),
    ]


IID_IApplicationViewConsolidatedEventArgs = GUID(
    '{514449EC-7EA2-4DE7-A6A6-7DFBAAEBB6FB}'
)


class IApplicationViewConsolidatedEventArgs(IInspectable):
    _case_insensitive_ = True
    _iid_ = IID_IApplicationViewConsolidatedEventArgs
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method get_IsUserInitiated')],
            HRESULT,
            'get_IsUserInitiated',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
    ]


IID_IApplicationView = GUID(
    '{D222D519-4361-451E-96C4-60F4F9742DB0}'
)


class IApplicationView(IInspectable):
    _case_insensitive_ = True
    _iid_ = IID_IApplicationView
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method get_Orientation')],
            HRESULT,
            'get_Orientation',
            (['retval', 'out'], POINTER(ApplicationViewOrientation), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_AdjacentToLeftDisplayEdge')],
            HRESULT,
            'get_AdjacentToLeftDisplayEdge',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_AdjacentToRightDisplayEdge')],
            HRESULT,
            'get_AdjacentToRightDisplayEdge',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_IsFullScreen')],
            HRESULT,
            'get_IsFullScreen',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_IsOnLockScreen')],
            HRESULT,
            'get_IsOnLockScreen',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_IsScreenCaptureEnabled')],
            HRESULT,
            'get_IsScreenCaptureEnabled',
            (['retval', 'out'], POINTER(BOOL), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method put_IsScreenCaptureEnabled')],
            HRESULT,
            'put_IsScreenCaptureEnabled',
            (['in'], BOOL, 'value'),
        ),
        COMMETHOD(
            [helpstring('Method put_Title')],
            HRESULT,
            'put_Title',
            (['in'], HSTRING, 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_Title')],
            HRESULT,
            'get_Title',
            (['retval', 'out'], POINTER(HSTRING), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method get_Id')],
            HRESULT,
            'get_Id',
            (['retval', 'out'], POINTER(INT32), 'value'),
        ),
        COMMETHOD(
            [helpstring('Method add_Consolidated')],
            HRESULT,
            'add_Consolidated',
            (['in'], POINTER(IApplicationViewConsolidatedEventArgs), 'handler'),
            (['retval', 'out'], POINTER(EventRegistrationToken), 'token'),
        ),
        COMMETHOD(
            [helpstring('Method remove_Consolidated')],
            HRESULT,
            'remove_Consolidated',
            (['in', ], EventRegistrationToken, 'EventRegistrationToken'),
        ),
    ]


IID_IServiceProvider = GUID(
    '{6D5140C1-7436-11CE-8034-00AA006009FA}'
)


class IServiceProvider(comtypes.IUnknown):
    _case_insensitive_ = True
    _idlflags_ = []
    _iid_ = IID_IServiceProvider
    _methods_ = [
        COMMETHOD(
            [helpstring('Method QueryService'), 'local', 'in'],
            HRESULT,
            'QueryService',
            (['in'], REFGUID, 'guidService'),
            (['in'], REFIID, 'riid'),
            (['out'], POINTER(LPVOID), 'ppvObject'),
        ),
    ]


IID_IObjectArray = GUID(
    "{92CA9DCD-5622-4BBA-A805-5E9F541BD8C9}"
)


class IObjectArray(comtypes.IUnknown):
    """
    Unknown Object Array
    """
    _case_insensitive_ = True
    _idlflags_ = []
    _iid_ = None

    _methods_ = [
        COMMETHOD(
            [helpstring('Method GetCount')],
            HRESULT,
            'GetCount',
            (['out'], POINTER(UINT), 'pcObjects'),
        ),
        COMMETHOD(
            [helpstring('Method GetAt')],
            HRESULT,
            'GetAt',
            (['in'], UINT, 'uiIndex'),
            (['in'], REFIID, 'riid'),
            (['out', 'iid_is'], POINTER(LPVOID), 'ppv'),
        ),
    ]


IID_IVirtualDesktop = GUID(
    '{FF72FFDD-BE7E-43FC-9C03-AD81681E88E4}'
)


class IVirtualDesktop(comtypes.IUnknown):
    _case_insensitive_ = True
    _iid_ = IID_IVirtualDesktop
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method IsViewVisible')],
            HRESULT,
            'IsViewVisible',
            (['out'], POINTER(IApplicationView), 'pView'),
            (['out'], POINTER(INT), 'pfVisible'),
        ),
        COMMETHOD(
            [helpstring('Method GetID')],
            HRESULT,
            'GetID',
            (['out'], POINTER(GUID), 'pGuid'),
        )
    ]


IID_IVirtualDesktopManager = GUID(
    '{A5CD92FF-29BE-454C-8D04-D82879FB3F1B}'
)


class IVirtualDesktopManager(comtypes.IUnknown):
    _case_insensitive_ = True
    _iid_ = IID_IVirtualDesktopManager
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method IsWindowOnCurrentVirtualDesktop')],
            HRESULT,
            'IsWindowOnCurrentVirtualDesktop',
            (['in'], HWND, 'topLevelWindow'),
            (['out'], POINTER(BOOL), 'onCurrentDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method GetWindowDesktopId')],
            HRESULT,
            'GetWindowDesktopId',
            (['in'], HWND, 'topLevelWindow'),
            (['out'], POINTER(GUID), 'desktopId'),
        ),
        COMMETHOD(
            [helpstring('Method MoveWindowToDesktop')],
            HRESULT,
            'MoveWindowToDesktop',
            (['in'], HWND, 'topLevelWindow'),
            (['in'], REFGUID, 'desktopId'),
        ),
    ]


CLSID_VirtualDesktopManagerInternal = GUID(
    '{C5E0CDCA-7B6E-41B2-9FC4-D93975CC467B}'
)

IID_IVirtualDesktopManagerInternal = GUID(
    '{F31574D6-B682-4CDC-BD56-1827860ABEC6}'
)


# IID_IVirtualDesktopManagerInternal = GUID(
#     '{AF8DA486-95BB-4460-B3B7-6E7A6B2962B5}'
# )

# IID_IVirtualDesktopManagerInternal = GUID(
#     '{EF9F1A6C-D3CC-4358-B712-F84B635BEBE7}'
# )

class IVirtualDesktopManagerInternal(comtypes.IUnknown):
    _case_insensitive_ = True
    _iid_ = IID_IVirtualDesktopManagerInternal
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method GetCount')],
            HRESULT,
            'GetCount',
            (['out'], POINTER(UINT), 'pCount'),
        ),
        COMMETHOD(
            [helpstring('Method MoveViewToDesktop')],
            HRESULT,
            'MoveViewToDesktop',
            (['out'], POINTER(IApplicationView), 'pView'),
            (['out'], POINTER(IVirtualDesktop), 'pDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method CanViewMoveDesktops')],
            HRESULT,
            'CanViewMoveDesktops',
            (['out'], POINTER(IApplicationView), 'pView'),
            (['out'], POINTER(INT), 'pfCanViewMoveDesktops'),
        ),
        COMMETHOD(
            [helpstring('Method GetCurrentDesktop')],
            HRESULT,
            'GetCurrentDesktop',
            (['out'], POINTER(POINTER(IVirtualDesktop)), 'desktop'),
        ),
        COMMETHOD(
            [helpstring('Method GetDesktops')],
            HRESULT,
            'GetDesktops',
            (['out'], POINTER(POINTER(IObjectArray)), 'ppDesktops'),
        ),
        COMMETHOD(
            [helpstring('Method GetAdjacentDesktop')],
            HRESULT,
            'GetAdjacentDesktop',
            (['out'], POINTER(IVirtualDesktop), 'pDesktopReference'),
            (['in'], AdjacentDesktop, 'uDirection'),
            (['out'], POINTER(POINTER(IVirtualDesktop)), 'ppAdjacentDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method SwitchDesktop')],
            HRESULT,
            'SwitchDesktop',
            (['in'], POINTER(IVirtualDesktop), 'pDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method CreateDesktopW')],
            HRESULT,
            'CreateDesktopW',
            (['out'], POINTER(POINTER(IVirtualDesktop)), 'ppNewDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method RemoveDesktop')],
            HRESULT,
            'RemoveDesktop',
            (['in'], POINTER(IVirtualDesktop), 'pRemove'),
            (['in'], POINTER(IVirtualDesktop), 'pFallbackDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method FindDesktop')],
            HRESULT,
            'FindDesktop',
            (['in'], POINTER(GUID), 'desktopId'),
            (['out'], POINTER(POINTER(IVirtualDesktop)), 'ppDesktop'),
        ),
    ]


IID_IVirtualDesktopNotification = GUID(
    '{C179334C-4295-40D3-BEA1-C654D965605A}'
)


class IVirtualDesktopNotification(comtypes.IUnknown):
    _case_insensitive_ = True
    _iid_ = IID_IVirtualDesktopNotification
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method VirtualDesktopCreated')],
            HRESULT,
            'VirtualDesktopCreated',
            (['in'], POINTER(IVirtualDesktop), 'pDesktop'),
        ),
        COMMETHOD(
            [helpstring('Method VirtualDesktopDestroyBegin')],
            HRESULT,
            'VirtualDesktopDestroyBegin',
            (['in'], POINTER(IVirtualDesktop), 'pDesktopDestroyed'),
            (['in'], POINTER(IVirtualDesktop), 'pDesktopFallback'),
        ),
        COMMETHOD(
            [helpstring('Method VirtualDesktopDestroyFailed')],
            HRESULT,
            'VirtualDesktopDestroyFailed',
            (['in'], POINTER(IVirtualDesktop), 'pDesktopDestroyed'),
            (['in'], POINTER(IVirtualDesktop), 'pDesktopFallback'),
        ),
        COMMETHOD(
            [helpstring('Method VirtualDesktopDestroyed')],
            HRESULT,
            'VirtualDesktopDestroyed',
            (['in'], POINTER(IVirtualDesktop), 'pDesktopDestroyed'),
            (['in'], POINTER(IVirtualDesktop), 'pDesktopFallback'),
        ),
        COMMETHOD(
            [helpstring('Method ViewVirtualDesktopChanged')],
            HRESULT,
            'ViewVirtualDesktopChanged',
            (['in'], POINTER(IApplicationView), 'pView'),
        ),
        COMMETHOD(
            [helpstring('Method CurrentVirtualDesktopChanged')],
            HRESULT,
            'CurrentVirtualDesktopChanged',
            (['in'], POINTER(IVirtualDesktop), 'pDesktopOld'),
            (['in'], POINTER(IVirtualDesktop), 'pDesktopNew'),
        ),
    ]


IID_IVirtualDesktopNotificationService = GUID('{0CD45E71-D927-4F15-8B0A-8FEF525337BF}')


class IVirtualDesktopNotificationService(comtypes.IUnknown):
    _case_insensitive_ = True
    _iid_ = IID_IVirtualDesktopNotificationService
    _idlflags_ = []
    _methods_ = [
        COMMETHOD(
            [helpstring('Method Register')],
            HRESULT,
            'Register',
            (['in'], POINTER(IVirtualDesktopNotification), 'pNotification'),
            (['out'], POINTER(DWORD), 'pdwCookie'),
        ),

        COMMETHOD(
            [helpstring('Method Unregister')],
            HRESULT,
            'Unregister',
            (['in'], DWORD, 'dwCookie'),
        ),
    ]


comtypes.CoInitialize()

pServiceProvider = comtypes.CoCreateInstance(
    CLSID_ImmersiveShell,
    IServiceProvider,
    comtypes.CLSCTX_LOCAL_SERVER,
)

pDesktopManagerInternal = comtypes.cast(
    pServiceProvider.QueryService(
        CLSID_VirtualDesktopManagerInternal,
        IID_IVirtualDesktopManagerInternal
    ),
    ctypes.POINTER(IVirtualDesktopManagerInternal)
)

pObjectArray = POINTER(IObjectArray)()

pDesktopManagerInternal.GetDesktops(ctypes.byref(pObjectArray))

count = UINT()
pObjectArray.GetCount(ctypes.byref(count))

for i in range(count):
    pDesktop = POINTER(IVirtualDesktop)()
    pObjectArray.GetAt(i, IID_IVirtualDesktop, ctypes.byref(pDesktop))

    id = GUID()
    pDesktop.GetID(ctypes.byref(id))

    print(id)

Thank you very much for this, I've made it work with [some modifications](https://github.com/DanEdens/Virtual_Desktops_Plugin/issues/1). — ipaleka, Jul 25 '19 at 17:21

score 0 · Answer 2 · answered Jul 25 '19 at 07:35

0

QueryInterface is the function that checks if a COM object has the wanted Interface and "cast" it to the new Interface

from the API, you can see that QueryInterface receives a GUID and as an output parameter of the new object pointer.

answered Jul 25 '19 at 07:35

Baget

3,318
1
24
44

I edited my question; am I doing my calls wrong or it's just self-explainable with 'No such interface supported'? – ipaleka Jul 25 '19 at 11:52

How to implement Windows 10 IVirtualDesktopManager interface in Python?

2 Answers2