The container control sends a WM_CONTROL (in Container Controls) message with the CN_DRAGOVER notification code to its owner when the container receives a DM_DRAGOVER message. The CN_DRAGOVER notification code is sent only if the CA_ORDEREDTARGETEMPH attribute of the CNRINFO data structure is not set or the current view is the icon view or tree view.

param1
     USHORT        id            /*  Container control ID. */
     USHORT        CN_DRAGOVER   /*  Notification code. */

param2
     PCNRDRAGINFO  pCnrDragInfo  /*  Pointer to a CNRDRAGINFO structure. */

returns
     USHORT        usDrop        /*  Drop indicator. */
     USHORT        usDefaultOp   /*  Default operation. */