How does the shortcut property sheet change icons instantly? - windows

Question

When you change the icon in the shortcut property sheet, the shortcut icon changes instantly.
When you run the Python script multiple times, you see the shortcut icons change each time to a random icon. However, when you comment out the create_internet_shortcut call in main, the icon of the manually written Internet shortcut "Bing.url" stops changing. There must be some additional processing that happens in the COM method after SHChangeNotify, which alone is not enough.
What do I need to do to make the Internet shortcut icon change when the URL file is written manually without using COM?
I have also tried calling SHChangeNotify 4 different times, but that didn't work. See the update_all_icons function and commented out call in main.
Install:
pip install pywin32
Code:
#!/usr/bin/env python
from typing import Any, Tuple
import os
import random
import traceback
from pathlib import Path
from win32com import storagecon
from win32comext.shell import shell, shellcon
import win32gui
import pythoncom
import pywintypes
system_icon_file = r"%SystemRoot%\System32\shell32.dll"
system_icon_max_index = 326
desktop_path = Path(r"~\Desktop").expanduser()
def create_internet_shortcut(path: str, target: str = None) -> None:
shortcut = pythoncom.CoCreateInstance(
shell.CLSID_InternetShortcut,
None,
pythoncom.CLSCTX_INPROC_SERVER,
shell.IID_IUniformResourceLocator
)
persist_file = shortcut.QueryInterface(pythoncom.IID_IPersistFile)
persist_file.Load(path)
if not isinstance(target, str):
target = shortcut.GetURL()
if target is None:
target = "https://www.bing.com/"
shortcut.SetURL(target)
property_set_storage = shortcut.QueryInterface(pythoncom.IID_IPropertySetStorage)
property_storage = property_set_storage.Open(shell.FMTID_Intshcut, storagecon.STGM_READWRITE)
icon_file = system_icon_file
icon_index = random.randint(0, system_icon_max_index)
property_storage.WriteMultiple((shellcon.PID_IS_ICONFILE, shellcon.PID_IS_ICONINDEX), (icon_file, icon_index))
property_storage.Commit(storagecon.STGC_DEFAULT)
persist_file.Save(path, 0)
def create_link_shortcut(path: str, target: str = "%SystemDrive%") -> None:
shortcut = pythoncom.CoCreateInstance(
shell.CLSID_ShellLink,
None,
pythoncom.CLSCTX_INPROC_SERVER,
shell.IID_IShellLink
)
persist_file = shortcut.QueryInterface(pythoncom.IID_IPersistFile)
try:
persist_file.Load(path)
except pywintypes.com_error:
traceback.print_exc()
shortcut.SetPath(target)
icon_file = system_icon_file
icon_index = random.randint(0, system_icon_max_index)
shortcut.SetIconLocation(icon_file, icon_index)
persist_file.Save(path, 0)
def write_internet_shortcut(path: str, target: str = None) -> None:
if not isinstance(target, str):
target = "https://www.bing.com/"
icon_file = system_icon_file
icon_index = random.randint(0, system_icon_max_index)
text = f"""[InternetShortcut]
URL={target}
IconFile={icon_file}
IconIndex={icon_index}"""
with open(path, "w", encoding="utf8") as file:
file.write(text)
def update_icon(path: str) -> None:
shell.SHChangeNotify(shellcon.SHCNE_UPDATEITEM, shellcon.SHCNF_PATHW | shellcon.SHCNF_FLUSHNOWAIT, path, None)
def update_all_icons(path: str) -> None:
result, info = shell.SHGetFileInfo(
path,
0,
shellcon.SHGFI_ICON | shellcon.SHGFI_DISPLAYNAME | shellcon.SHGFI_TYPENAME
)
hIcon, iIcon, dwAttributes, displayName, typeName = info
print("Info:", info)
if iIcon > 0:
shell.SHChangeNotify(shellcon.SHCNE_UPDATEIMAGE, shellcon.SHCNF_DWORD | shellcon.SHCNF_FLUSHNOWAIT, iIcon, None)
shell.SHChangeNotify(shellcon.SHCNE_ASSOCCHANGED, shellcon.SHCNF_DWORD | shellcon.SHCNF_FLUSHNOWAIT, iIcon, None)
shell.SHChangeNotify(shellcon.SHCNE_UPDATEITEM, shellcon.SHCNF_PATHW | shellcon.SHCNF_FLUSHNOWAIT, path, None)
shell.SHChangeNotify(shellcon.SHCNE_UPDATEDIR, shellcon.SHCNF_PATHW | shellcon.SHCNF_FLUSHNOWAIT, str(desktop_path.resolve()), None)
win32gui.DestroyIcon(hIcon)
def main(*args: Tuple[Any, ...]) -> None:
create_internet_shortcut(str(desktop_path.joinpath("COM Internet.url").resolve()))
create_link_shortcut(str(desktop_path.joinpath("COM link.lnk").resolve()))
bing_file_path = str(desktop_path.joinpath("Bing.url").resolve())
write_internet_shortcut(bing_file_path)
update_icon(bing_file_path)
# update_all_icons(bing_file_path)
if __name__ == "__main__":
main()