How to refresh the folder icon instantly in Windows

Question

I am now programming a small tool and need to refresh the folder icon instantly.
As we know, in Windows, we could modify folder icons by the following steps manually:

1. right click the folder
   
2. choose "customize" tag
   
3. click "change icon"
   

I also know how to set the desktop.ini file to modify its icon. But it takes really a long time to refresh (about 30 seconds).

I wanna know if there is a common way to solve it instantly no matter using C/C++ or script. Or Windows never provides a way?

Answer 1

This small C program will do the job:

#include <windows.h>
#include <ShlObj.h>

const char folderpath[] = "C:\\Your-Folder";

int main() {
  SHChangeNotify(SHCNE_UPDATEITEM, SHCNF_PATH, folderPath, NULL);
}

folderpath is the full path to the folder whose icon is to be updated Following sequence of operations works fine here (Windows 10 64 bits):

Desktop.ini file

[.ShellClassInfo]
IconResource=C:\Windows\System32\SHELL32.dll,12

1. Create a folder X
2. Copy the Desktop.ini file above into the folder. The icon of the X folder will not change
3. Run the small C program above
4. The new icon is displayed on the X folder
5. Remove the Deskop.ini file created at point 2. The icon of the X folder will not change
6. Run the small C program above
7. The original folder icon is displayed on the X folder

Check the SHChangeNotify function for more details.