SetScrollPos

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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.

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 Values

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 versions 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

Runs on	Versions	Defined in	Include	Link to
Windows CE OS	2.0 and later	Winuser.h		Sbcmn.lib

Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.