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SetScrollInfo function

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 fnBar,
  _In_  LPCSCROLLINFO lpsi,
  _In_  BOOL fRedraw
);

Parameters

hwnd [in]

Type: HWND

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

fnBar [in]

Type: int

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

ValueMeaning
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.

 

lpsi [in]

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.

ValueMeaning
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.

 

fRedraw [in]

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

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Winuser.h (include Windows.h)

Library

User32.lib

DLL

User32.dll

See also

Reference
GetScrollInfo
SCROLLINFO

 

 

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