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
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)