This notification message is sent by a header control when a drag operation has begun on one of its items. It is sent only by header controls set to the HDS_DRAGDROP style, and is sent as a WM_NOTIFY message.
At a Glance
| Header file: | Commctrl.h |
| Windows CE versions: | 2.0 and later |
Syntax
HDN_BEGINDRAG pNMHeader = (LPNMHEADER) lParam;
Parameters
pNMHeader
Pointer to an NMHEADER structure that contains data about the header item dragged
Return Values
To enable the header control to automatically manage drag-and-drop operations, return FALSE. If the owner of the control is manually performing drag-and-drop reordering, return TRUE.
Remarks
A header control defaults to automatically managing drag-and-drop reordering. Returning TRUE to indicate external (manual) drag-and-drop management enables the owner of the control to provide custom services as part of the drag-and-drop process.