UDN_DELTAPOS (Windows Embedded CE 6.0)

1/6/2010

This message is sent by the OS to the parent window of an up-down control when the position of the control is about to change. This happens when the user requests a change in the value by pressing the control's up or down arrow. It is sent in the form of a WM_NOTIFY message.

Syntax

UDN_DELTAPOS lpnmud = (NM_UPDOWN FAR *) lParam

Parameters

• lpnmud
  Long pointer to an NMUPDOWN structure that contains information about the position change.

  The iPos member of this structure contains the current position of the control. The iDelta member of the structure is a signed integer that contains the proposed change in position. If the user has clicked the up button, this is a positive value. If the user has clicked the down button, this is a negative value.

Return Value

Nonzero prevents the change in the control's position. Zero accepts the change.

Remarks

The UDN_DELTAPOS message is sent before the WM_HSCROLL message, which actually changes the control's position. This enables you to examine, accept, modify, or reject the change.

Requirements

See Also

Reference

Up-Down Controls Messages
NMUPDOWN
WM_COMMAND
WM_VSCROLL