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_NODROP 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. Ordered 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)