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GetScrollBarInfo function

Applies to: desktop apps only

The GetScrollBarInfo function retrieves information about the specified scroll bar.

Syntax

Copy

BOOL GetScrollBarInfo(
  __in   HWND hwnd,
  __in   LONG idObject,
  __out  PSCROLLBARINFO psbi
);

Parameters

hwnd [in]

Type: HWND

Handle to a window associated with the scroll bar whose information is to be retrieved. If the idObject parameter is OBJID_CLIENT, hwnd is a handle to a scroll bar control. Otherwise, hwnd is a handle to a window created with WS_VSCROLL and/or WS_HSCROLL style.

idObject [in]

Type: LONG

Specifies the scroll bar object. This parameter can be one of the following values.

Value	Meaning
OBJID_CLIENT	The hwnd parameter is a handle to a scroll bar control.
OBJID_HSCROLL	The horizontal scroll bar of the hwnd window.
OBJID_VSCROLL	The vertical scroll bar of the hwnd window.

psbi [out]

Type: PSCROLLBARINFO

Pointer to a SCROLLBARINFO structure to receive the information. Before calling GetScrollBarInfo, set the cbSize member to sizeof(SCROLLBARINFO).

Return value

Type: BOOL

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

If idObject is OBJID_CLIENT and the window specified by hwnd is not a system scroll bar control, the system sends the SBM_GETSCROLLBARINFO message to the window to obtain scroll bar information. This allows GetScrollBarInfo to operate on a custom control that mimics a scroll bar. If the window does not handle the SBM_GETSCROLLBARINFO message, the GetScrollBarInfo function fails.

Requirements

Minimum supported client	Windows 2000 Professional
Minimum supported server	Windows 2000 Server
Redistributable	Service Pack 6
Header	Winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll

There are two more bugs in this command:

1.)
The width of a horizontal scrollbar thumb is never shorter than SM_CXHTHUMB (17 pixel) in some applications with Comctl 6.1
The width of a horizontal scrollbar thumb is never shorter than 8 pixel in some other applications with Comctl 5.82
This way the scrollbar is painted inconsistent depending on the ComCtl32.dll version.
But GetScrollBarInfo retuns always the 8 pixel minimum thumb width although the scrollbar thumb is painterd as 17 pixel by Comctl version 6.1.

2.)
If you test the whole stuff in a dialog with WS_EX_LAYOUTRTL it becomes even worse.
Now the horizontal scrollbar returns a completely invalid thumb position.
This applies to ComCtl version 5.8 and 6.0.

The strangest thing is that a Scrollbar control (OBJID_CLIENT) works correctly while the bugs affect only OBJID_HSCROLL and OBJID_VSCROLL!

History

10/16/2011
ElmueSoft

10/24/2011
ElmueSoft

This command is completely buggy

When you execute GetScrollBarInfo or send SBM_GETSCROLLBARINFO with OBJID_CLIENT on Windows XP SP3 for a scrollbar that has an own Window handle, the command will fail.
It returns FALSE and GetLastError() returns 0 if called from the GUI thread.
It returns FALSE and GetLastError() returns ERROR_MORE_DATA or ERROR_FILE_NOT_FOUND if called from another thread.
This applies only to applications that use ComCtl.dll version 6.

This does not apply to applications that use ComCtl.dll version 5.
This does not apply to Windows Vista.
This does not apply to OBJID_HSCROLL and OBJID_VSCROLL.
___________________________________________________________

There is another bug at least on Windows Vista:
If you call this command with OBJID_CLIENT on a Gripper the returned rcScrollBar has a size of 0x0 pixels.