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SetScrollInfo function (winuser.h)

  • Článek

The SetScrollInfo function sets the parameters of a scroll bar, including the minimum and maximum scrolling positions, the page size, and the position of the scroll box (thumb). The function also redraws the scroll bar, if requested.

Syntax

int SetScrollInfo(
  [in] HWND          hwnd,
  [in] int           nBar,
  [in] LPCSCROLLINFO lpsi,
  [in] BOOL          redraw
);

Parameters

[in] hwnd

Type: HWND

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

[in] nBar

Type: int

Specifies the type of scroll bar for which to set parameters. This parameter can be one of the following values.

Value Meaning
SB_CTL
 Sets the parameters of a scroll bar control. The hwnd parameter must be the handle to the scroll bar control.
SB_HORZ
 Sets the parameters of the window's standard horizontal scroll bar.
SB_VERT
 Sets the parameters of the window's standard vertical scroll bar.

[in] lpsi

Type: LPCSCROLLINFO

Pointer to a SCROLLINFO structure. Before calling SetScrollInfo, set the cbSize member of the structure to sizeof(SCROLLINFO), set the fMask member to indicate the parameters to set, and specify the new parameter values in the appropriate members.

The fMask member can be one or more of the following values.

Value Meaning
SIF_DISABLENOSCROLL
 Disables the scroll bar instead of removing it, if the scroll bar's new parameters make the scroll bar unnecessary.
SIF_PAGE
 Sets the scroll page to the value specified in the nPage member of the SCROLLINFO structure pointed to by lpsi.
SIF_POS
 Sets the scroll position to the value specified in the nPos member of the SCROLLINFO structure pointed to by lpsi.
SIF_RANGE
 Sets the scroll range to the value specified in the nMin and nMax members of the SCROLLINFO structure pointed to by lpsi.

[in] redraw

Type: BOOL

Specifies whether the scroll bar is redrawn to reflect the changes to the scroll bar. If this parameter is TRUE, the scroll bar is redrawn, otherwise, it is not redrawn.

Return value

Type: int

The return value is the current position of the scroll box.

Remarks

The SetScrollInfo function performs range checking on the values specified by the nPage and nPos members of the SCROLLINFO structure. The nPage member must specify a value from 0 to nMax - nMin +1. The nPos member must specify a value between nMin and nMax - max( nPage– 1, 0). If either value is beyond its range, the function sets it to a value that is just within the range.

If the fnBar parameter is SB_CTL and the window specified by the hwnd parameter is not a system scroll bar control, the system sends the SBM_SETSCROLLINFO message to the window to set scroll bar information (The system can optimize the message to SBM_SETPOS or SBM_SETRANGE if the request is solely for the position or range). This allows SetScrollInfo to operate on a custom control that mimics a scroll bar. If the window does not handle SBM_SETSCROLLINFO (or the optimized SBM_SETPOS message or SBM_SETRANGE message), then the SetScrollInfo function fails.

For an example, see Scrolling Text with the WM_PAINT Message.

Requirements

Requirement Value
Minimum supported client Windows Vista [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header winuser.h (include Windows.h)
Library User32.lib
DLL User32.dll
API set ext-ms-win-ntuser-misc-l1-2-0 (introduced in Windows 8.1)

See also

GetScrollInfo

Reference

SCROLLINFO