This notification code shows where direct manipulation is occurring by applying target emphasis to indicate whether an item that is being dragged over the container can be dropped. It is not necessary for the application to draw any target emphasis for the container when it receives this notification code.

If the pointer is over a container record and the item that is being dragged can be dropped on that record, the container draws a black rectangle around the target record. If the pointer is over white space and the item that is being dragged can be dropped on the white space, the container draws a black border around the edge of the client area.

If the container returns anything except DOR_DROP, the target emphasis is automatically changed to a symbol that indicates no drop is allowed. This gives the user a visual cue that a drop cannot occur. The symbol reverts to the black rectangle or black border when the container returns a DOR_DROP reply.

The CN_DRAGOVER notification code is sent only for the icon and tree views, or when the CA_ORDEREDTARGETEMPH attribute of the CNRINFO data structure is not set. If this attribute is set and the current view is the name, text, or details view, the CN_DRAGAFTER notification code is sent.

The return parameter is reserved.