ShowScrollBar function (winuser.h)

The ShowScrollBar function shows or hides the specified scroll bar.

BOOL ShowScrollBar(
  [in] HWND hWnd,
  [in] int  wBar,
  [in] BOOL bShow
);

[in] hWnd

Type: HWND

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

[in] wBar

Type: int

Specifies the scroll bar(s) to be shown or hidden. This parameter can be one of the following values.

[in] bShow

Type: BOOL

Specifies whether the scroll bar is shown or hidden. If this parameter is TRUE, the scroll bar is shown; otherwise, it is hidden.

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.

You should not call this function to hide a scroll bar while processing a scroll bar message.

EnableScrollBar