CN QUERYDELTA

This message is sent by the container control to its owner to query for more data when a user scrolls to a preset delta value.

Syntax

param1
USHORT id;            /* Container control ID. */
USHORT CN_QUERYDELTA; /* Notification code. */

param2
PNOTIFYDELTA pNotifyDelta; /* Pointer to the NOTIFYDELTA structure. */

Parameters

id (USHORT) - Input

Container control ID.

CN_QUERYDELTA (USHORT) - Input

Notification code.

pNotifyDelta (PNOTIFYDELTA) - Input

Pointer to the NOTIFYDELTA structure.

Returns

ulReserved (ULONG) - returns

Reserved value, should be 0.

Remarks

The delta value is specified by the cDelta field of the CNRINFO data structure and is set with the CMA_DELTA attribute of the CM_SETCNRINFO message. If the value of the cDelta field is greater than 0 and a user scrolls to the threshold record, the container control sends a CN_QUERYDELTA notification code to the application. The application can then insert more records into the container. It may be necessary for the application to remove some records before inserting records.

Default Processing

The default window procedure does not expect to receive this notification code and therefore takes no action on it other than to return 0.