CWnd::GetScrollInfo

BOOL GetScrollInfo( int nBar, LPSCROLLINFO lpScrollInfo, UINT nMask = SIF_ALL );

Return Value

If the message retrieved any values, the return is TRUE. Otherwise, it is FALSE.

Parameters

nBar

Specifies whether the scroll bar is a control or part of a window’s nonclient area. If it is part of the nonclient area, nBar also indicates whether the scroll bar is positioned horizontally, vertically, or both. It must be one of the following:

SB_CTL Contains the parameters for a scroll bar control. The m_hWnd data member must be the handle of the scroll bar control.
SB_HORZ Specifies that the window is a horizontal scroll bar.
SB_VERT Specifies that the window is a vertical scroll bar.

lpScrollInfo

A pointer to a SCROLLINFO structure. See the Win32 SDK Programmer’s Reference for more information about this structure.

nMask

Specifies the scroll bar parameters to retrieve. The default specifies a combination of SIF_PAGE, SIF_POS, SIF_TRACKPOS, and SIF_RANGE. See SCROLLINFO for more information on the nMask values.

Remarks

Call this member function to retrieve the information that the SCROLLINFO structure maintains about a scroll bar. GetScrollInfo enables applications to use 32-bit scroll positions.

The SCROLLINFO structure contains information about a scroll bar, including the minimum and maximum scrolling positions, the page size, and the position of the scroll box (the thumb). See the SCROLLINFO structure topic in the Win32 SDK Programmer’s Reference for more information about changing the structure defaults.

The MFC Windows message handlers that indicate scroll-bar position, CWnd::OnHScroll and CWnd::OnVScroll, provide only 16 bits of position data. GetScrollInfo and SetScrollInfo provide 32 bits of scroll-bar position data. Thus, an application can call GetScrollInfo while processing either CWnd::OnHScroll or CWnd::OnVScroll to obtain 32-bit scroll-bar position data.

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