There is no one that i can ask. help me..
I did hooking DoDragDrop API at the desktop(explorer.exe) and then dropped a text file on some UWP applications from desktop.
The UWP applications are 'Edge', 'Line'(messenger) and 'Mail'.
The file i dropped was attached successfully at the apps..
But the pdwEffect's value was 0 on the DoDragDropCallback function. In the Edge and Line.
Its value wasn't zero in the Mail.
zero value is DROPEFFECT_NONE(Drop target cannot accept the data.)
Do you know why??
in a call to ChangeWindowMessageFilter()
I used a spy++ program in order to look the WM(WM_DROPFILE, COPY .. )at the Edge.
But There was no any WM.