Initializing Drag and Drop

To support drag-and-drop operations, the application must call the Drag-AcceptFiles function and must notify the rich edit control that it should pass along any ENM_DROPFILES notifications. By default, the notification is not sent to the parent of the rich edit control.

// Register to allow drag and drop.
DragAcceptFiles (hWndRichEdit, TRUE);

// Tell the rich edit control that you want to allow drag and drop.
SendMessage (hWndRichEdit, EM_SETEVENTMASK, 0, (LPARAM)ENM_DROPFILES);