id (USHORT)

Container control ID.

CN_DRAGOVER (USHORT)

Notification code.

pCnrDragInfo (PCNRDRAGINFO)

Pointer to a CNRDRAGINFO structure.

usDrop (USHORT)

Drop indicator.

DOR_DROP

The record can be dropped. When this response is returned, the container control applies target emphasis.
DOR_NODROP
The record is acceptable and the current operation is supported by the target, but the record cannot be dropped in the current location. For example, the container control returns DOR_DROP if the record being dragged is positioned over another record on which it cannot be dropped.

If the container returns DOR_NODROP, the DM_DRAGOVER message will continue to be sent to it when the user does any of the following:

• Moves the pointer 
  Presses a keyboard key
  
  Moves the pointer out of and back into the container window.
  DOR_NODROPOP
  The record is acceptable, but the target does not support the current operation. This response implies that the drop may be valid if the drag operation changes. For example, if the default operation is copy and the target does not support this operation, the drop may become valid if the user presses a keyboard augmentation key to change to a different operation, such as move.

  If the container returns DOR_NODROPOP, no further DM_DRAGOVER messages are sent until the user does any of the following:

  • Presses a keyboard key 
    Moves the pointer out of and back into the container window.
    DOR_NEVERDROP
    The record cannot be dropped. Target emphasis is not drawn. If the container returns DOR_NEVERDROP, no further DM_DRAGOVER messages are sent until the user drags the record outside of and back into the container window.

    usDefaultOp (USHORT)

    Default operation.

    Target-defined default operation.

    DO_COPY

    Operation is a copy.
    DO_DEFAULT
    Operation is the default drag operation. No modifier keys are pressed.
    DO_LINK
    Operation is a link.
    DO_MOVE
    Operation is a move.
    DO_UNKNOWN
    Operation is application-defined.

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