GetScrollInfo

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This function retrieves the parameters of a scroll bar, including the minimum and maximum scrolling positions, the page size, and the position of the scroll box (thumb).

BOOL
GetScrollInfo(
HWND
hwnd
,
int
fnBar
,
LPSCROLLINFO
lpsi
);

Parameters

hwnd

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

fnBar

Specifies the type of scroll bar for which to retrieve parameters. It is one of the following values:

Value	Description
SB_CTL	Retrieves the parameters for a scroll bar control. The hwndparameter must be the handle to the scroll bar control.
SB_HORZ	Retrieves the parameters for the given window's standard horizontal scroll bar.
SB_VERT	Retrieves the parameters for the given window's standard vertical scroll bar.

lpsi

Long pointer to a SCROLLINFOstructure. Before calling GetScrollInfo, set the cbSizemember of the structure to sizeof( SCROLLINFO), and set the fMaskmember to specify the scroll bar parameters to retrieve. Before returning, the function copies the specified parameters to the appropriate members of the structure.

The fMaskmember can be a combination of the following values:

Value	Description
SIF_PAGE	Copies the scroll page to the nPagemember of the SCROLLINFOstructure pointed to by lpsi.
SIF_POS	Copies the scroll position to the nPosmember of the SCROLLINFOstructure pointed to by lpsi.
SIF_RANGE	Copies the scroll range to the nMinand nMaxmembers of the SCROLLINFOstructure pointed to by lpsi.
SIF_TRACKPOS	Copies the current scroll box tracking position to the nTrackPosmember of the SCROLLINFOstructure pointed to by lpsi.

Return Values

Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.

Remarks

The GetScrollInfofunction enables applications to use 32-bit scroll positions. Although the messages that indicate scroll-bar position, WM_HSCROLLand WM_VSCROLL, provide only 16 bits of position data, the functions SetScrollInfo and GetScrollInfoprovide 32 bits of scroll-bar position data. Thus, an application can call GetScrollInfowhile processing either the WM_HSCROLL or WM_VSCROLL messages to obtain 32-bit scroll-bar position data.

To get the 32-bit position of the scroll box (thumb) during a SB_THUMBTRACK notification in a WM_HSCROLL or WM_VSCROLL message, call GetScrollInfowith the SIF_TRACKPOS value in the fMaskmember of the SCROLLINFOstructure. The function returns the tracking position of the scroll box in the nTrackPosmember of the SCROLLINFOstructure. This allows you to get the position of the scroll box as the user moves it. The following sample code illustrates the technique.

SCROLLINFO si; case WM_HSCROLL:
switch(LOWORD(wparam)) { case SB_THUMBTRACK: // Initialize
SCROLLINFO structure ZeroMemory(&si, sizeof(SCROLLINFO));
si.cbSize = sizeof(SCROLLINFO); si.fMask = SIF_TRACKPOS; // Call
GetScrollInfo to get current tracking // position in si.nTrackPos
if (!GetScrollInfo(hwnd, SB_HORZ, &si) ) return 1; //
GetScrollInfo failed break; . . . }

Requirements

Runs on	Versions	Defined in	Include	Link to
Windows CE OS	1.0 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.