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4/8/2010

This function sets the position of the scroll box (thumb) in the specified scroll bar and, if requested, redraws the scroll bar to reflect the new position of the scroll box. SetScrollPosis provided for compatibility with Windows 3. x. Win32®-based applications should use the SetScrollInfofunction.

Syntax 

int SetScrollPos( 
  HWND 
hWnd, 
  int 
nBar, 
  int 
nPos, 
  BOOL 
bRedraw 
);

Parameters

hWnd

Handle to a scroll bar control or a window with a standard scroll bar, depending on the value of the nBarparameter.

nBar

Specifies the scroll bar to be set. This parameter can be one of the following values.

Value Description

SB_CTL

Sets the position of the scroll box in a scroll bar control. The hWndparameter must be the handle to the scroll bar control.

SB_HORZ

Sets the position of the scroll box in a window's standard horizontal scroll bar.

SB_VERT

Sets the position of the scroll box in a window's standard vertical scroll bar.
nPos

Specifies the new position of the scroll box. The position must be within the scrolling range. For more information about the scrolling range, see the SetScrollRangefunction.

bRedraw

Boolean that specifies whether the scroll bar is redrawn to reflect the new scroll box position. If this parameter is TRUE, the scroll bar is redrawn. If it is FALSE, the scroll bar is not redrawn.

Return Value

The previous position of the scroll box indicates success. Zero indicates failure. To get extended error information, call GetLastError.

Remarks

If the scroll bar is redrawn by a subsequent call to another function, setting the bRedrawparameter to FALSE is useful.

In Windows CE 2.12 and earlier, SetScrollPosreturns the new position of the scroll bar.

Because the messages that indicate scroll bar position, WM_HSCROLL and WM_VSCROLL, are limited to 16 bits of position data, applications that rely solely on those messages for position data have a practical maximum value of 65,535 for the SetScrollPosfunction's nPosparameter.

However, because the SetScrollInfo, SetScrollPos, SetScrollRange, GetScrollInfo, GetScrollPos, and GetScrollRangefunctions support 32-bit scroll bar position data, there is a way to circumvent the 16-bit barrier of the WM_HSCROLL and WM_VSCROLL messages. See GetScrollInfofor a description of the technique.

Requirements

Header winuser.h
Library Sbcmn.lib
Windows Embedded CE Windows CE 2.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also