Drag and drop not working on run as administrator

Pradeep Reddy

Hi all .. why drag and drop is not working in qml when we running application as administrator mode .. any solution .. to workaround for it .. one solution to modify registry key value 'EnableLUA' to 0 it is working but i don't want to modify registry .

mrjj

Hi
If you are talking about windows OS, its due to the fact that
administrator is run in another security context.
https://superuser.com/questions/59051/drag-and-drop-file-into-application-under-run-as-administrator

You try ( while running the app as adim)
launch cmd (Command Prompt) using Run As Administrator

Type:
taskkill /f /im explorer.exe
start explorer.exe

Then try to drag to your app and see if that makes any difference.

This is not isolated to Qt apps. btw.

xanadu

What I'm trying to say is that only QT has this problem! ! !

call the following function
// application
::ChangeWindowMessageFilter(WM_DROPFILES, MSGFLT_ADD);
::ChangeWindowMessageFilter(WM_COPYDATA, MSGFLT_ADD);
::ChangeWindowMessageFilter(WM_COPYGLOBALDATA, MSGFLT_ADD);

// window
::DragAcceptFiles(HWND, TRUE);
::ChangeWindowMessageFilterEx(HWND, WM_DROPFILES, MSGFLT_ALLOW, nullptr);
::ChangeWindowMessageFilterEx(HWND, WM_COPYDATA, MSGFLT_ALLOW, nullptr);
::ChangeWindowMessageFilterEx(HWND, WM_COPYGLOBALDATA, MSGFLT_ALLOW, nullptr);
When I use MFC, Win32, wxWidgets, there is no problem.

Only QT, called and nothing happens.
I don't understand, why my use of WinId doesn't work.
How exactly is it different from the HWND returned by CreateWindow?
Or, what is QT doing internally that causes these calls to fail.

xanadu

Here is the solution:
https://github.com/libxcc/QWidget-Admin-Drag

Obviously, Qt does have some problems under administrator privileges.
The drag-and-drop method used by Qt can display some icons on the interface, but it cannot respond when the administrator is in the administrator's role.
So we can only use alternative methods to bypass it and send events ourselves. The disadvantage is that the icon cannot be displayed. Alternatively, we can use Qt's method to add an icon, but I did not deal with it.